Let's practice Euler's Method using a few concrete examples.
+
Using Euler's Method 1
@@ -1407,13 +1408,9 @@
.
- Using Euler's method, we find the approximate y(2) \approx -0.75.
-
-
- To help visualize the Euler's method approximation, these three points
- (connected by line segments)
- are plotted along with the analytical solution to the initial value problem in .
+ Using Euler's method, we find the approximation y(2) \approx -0.75.
+
Euler's Method approximation to \yp = x + y with y(1) = -1 from ,
along with the analytical solution to the initial value problem
@@ -1452,6 +1449,12 @@
+
+
+ To help visualize the Euler's method approximation, these three points
+ (connected by line segments)
+ are plotted along with the analytical solution to the initial value problem in .
+
@@ -1498,7 +1501,7 @@
along with the points from and the analytic solution,
are plotted in .
-
+
Euler's Method approximations to \yp = x + y with y(1) = -1 from Examples
and , along with the analytical solution
@@ -1642,7 +1645,7 @@
are plotted in .
Notice how well they seem to match the true solution.
-
+
Euler's Method approximation to \yp = y(1-y) with y(0) = 0.25 from ,
along with the analytical solution
Video examples for difference quotients: once with direct computation, and then by simplifying first
diff --git a/ptx/sec_limit_onesided.ptx b/ptx/sec_limit_onesided.ptx
index 2f794a779..d1f0980a5 100644
--- a/ptx/sec_limit_onesided.ptx
+++ b/ptx/sec_limit_onesided.ptx
@@ -741,7 +741,7 @@
It is also clearly stated that f(1) = 1.
-
+ Video solution
diff --git a/ptx/sec_lines.ptx b/ptx/sec_lines.ptx
index 5f11d533a..de47c395a 100644
--- a/ptx/sec_lines.ptx
+++ b/ptx/sec_lines.ptx
@@ -706,7 +706,7 @@
Therefore, we conclude that the lines \ell_1 and \ell_2 are skew.
-
+ Video solution
@@ -939,7 +939,7 @@
.
-
+
Determining distance from a line to a point
diff --git a/ptx/sec_par_calc.ptx b/ptx/sec_par_calc.ptx
index e080451ee..8461bdf54 100644
--- a/ptx/sec_par_calc.ptx
+++ b/ptx/sec_par_calc.ptx
@@ -500,7 +500,7 @@
therefore the tangent line is y=0, the x-axis.
-
+ Video solution
@@ -1108,10 +1108,10 @@
Increasing n shows that this value is stable and a good approximation of the actual value.
-
+
diff --git a/ptx/sec_param_eqs.ptx b/ptx/sec_param_eqs.ptx
index a4f211604..8074f793f 100644
--- a/ptx/sec_param_eqs.ptx
+++ b/ptx/sec_param_eqs.ptx
@@ -1038,7 +1038,7 @@
the graph defined by y=1-x with unrestricted domain is given in a thin line.
-
+ Video solution
@@ -1110,7 +1110,7 @@
demonstrating that the graph is indeed of an ellipse with a horizontal major axis and center at (3,1).
-
+ Video solution
@@ -1576,7 +1576,7 @@
-
+ Video solution
diff --git a/ptx/sec_partial_fraction.ptx b/ptx/sec_partial_fraction.ptx
index ad58d32f6..08d6d20a5 100644
--- a/ptx/sec_partial_fraction.ptx
+++ b/ptx/sec_partial_fraction.ptx
@@ -86,15 +86,17 @@
-
+
+
+
To find the coefficients A_i,
B_i and C_i:
diff --git a/ptx/sec_planes.ptx b/ptx/sec_planes.ptx
index a7d1e2a54..82578d290 100644
--- a/ptx/sec_planes.ptx
+++ b/ptx/sec_planes.ptx
@@ -301,7 +301,7 @@
-
+ Video solution
@@ -530,7 +530,7 @@
-
+ Video solution
@@ -795,7 +795,7 @@
-
+ Video solution
diff --git a/ptx/sec_polar.ptx b/ptx/sec_polar.ptx
index affb0ac54..9c6e8f454 100644
--- a/ptx/sec_polar.ptx
+++ b/ptx/sec_polar.ptx
@@ -783,7 +783,7 @@
-
+ Video solution
@@ -2008,7 +2008,7 @@
- We start by setting the two functions equal to each other and solving for \theta:
+ To start we set the functions equal to each other and solve for \theta:
1+3\cos(\theta) \amp = \cos(\theta)2\cos(\theta) \amp = -1
@@ -2019,7 +2019,7 @@
(There are, of course,
- infinite solutions to the equation \cos(\theta) =-1/2;
+ infinitely many solutions to the equation \cos(\theta) =-1/2;
as the limaçon is traced out once on [0,2\pi],
we restrict our solutions to this interval.)
-
+ Video solution
@@ -601,7 +601,7 @@
We did this example to demonstrate that the area formula is correct.
-
+ Video solution
@@ -1169,7 +1169,7 @@
which is accurate to 4 places after the decimal.)
-
+ Video solution
diff --git a/ptx/sec_ratio_root_tests.ptx b/ptx/sec_ratio_root_tests.ptx
index 449d031f3..4c542b3a4 100644
--- a/ptx/sec_ratio_root_tests.ptx
+++ b/ptx/sec_ratio_root_tests.ptx
@@ -308,7 +308,7 @@
-
+
diff --git a/ptx/sec_series.ptx b/ptx/sec_series.ptx
index bba19d7cc..b4b4a0316 100644
--- a/ptx/sec_series.ptx
+++ b/ptx/sec_series.ptx
@@ -718,7 +718,7 @@
-
+ Video solution
diff --git a/ptx/sec_space_coord.ptx b/ptx/sec_space_coord.ptx
index 93eb2cd27..f77920f3c 100644
--- a/ptx/sec_space_coord.ptx
+++ b/ptx/sec_space_coord.ptx
@@ -746,7 +746,7 @@
-
+ Video solution
diff --git a/ptx/sec_stokes_divergence.ptx b/ptx/sec_stokes_divergence.ptx
index 873a934a5..802410e0e 100644
--- a/ptx/sec_stokes_divergence.ptx
+++ b/ptx/sec_stokes_divergence.ptx
@@ -685,6 +685,9 @@
one has power to select the easiest computation as illustrated next.
+
+
+
Using the Divergence Theorem to compute flux
@@ -705,8 +708,6 @@
.
-
-
The direct flux computation requires six surface integrals,
one for each face of the cube.
diff --git a/ptx/sec_tan_norm.ptx b/ptx/sec_tan_norm.ptx
index 6f2293ae0..098580294 100644
--- a/ptx/sec_tan_norm.ptx
+++ b/ptx/sec_tan_norm.ptx
@@ -140,7 +140,7 @@
\unittangent(1) to verify it has length 1.
-
+ Video solution
@@ -229,7 +229,7 @@
-
+ Video solution
@@ -441,7 +441,7 @@
-
+ Video solution
@@ -846,7 +846,7 @@
Here the particle's speed is not changing and all acceleration is in the form of direction change.
-
+ Video solution
diff --git a/ptx/sec_taylor_poly.ptx b/ptx/sec_taylor_poly.ptx
index 2be67c0e3..035a6e9aa 100644
--- a/ptx/sec_taylor_poly.ptx
+++ b/ptx/sec_taylor_poly.ptx
@@ -223,7 +223,67 @@
whose first four derivatives at 0 match those of f.
-
+
+
Plotting f, p_2 and p_4
+
+
+ The graph of a function and two polynomials that approximate the function near x=0.
+
+
+ The graph of a function f(x) is shown. It is the same function as the first image in this section,
+ but again, the precise details of the graph are unimportant.
+
+
+
+ Also shown are the graphs of two functions p_2(x) and p_4(x).
+ The function p_2(x) is quadratic, and its graph is a parabola that opens upward.
+ The function p_4(x) is a polynomial of degree 4.
+
+
+
+ All three graphs intersect at the point (0,f(0)),
+ and the values of both p_2(x) and p_4(x) are close to the value of f(x) when x is close to 0.
+ Two observations are important: first, both of these polynomial graphs appear to lie more closely to the graph of f(x)
+ than the tangent line in the first image. Second, the graph of p_4(x) is a good approximation to f(x)
+ over a larger interval than the graph of p_2(x).
+
+
+
+ In particular, the point (0,f(0)) appears to be a local minimum,
+ and there is a corresponding minimum in the graphs of both p_2(x) and p_4(x).
+ But the graph of f(x) also appears to have a local maximum near x=1.
+ Near x=1, the graph of p_2(x) separates from that of f(x):
+ the first continues to increase, while the second begins to decrease.
+ Near x=1, p_2(x) is no longer a good approximation to f(x).
+
+
+
+ However, the graph of p_4(x) also has a maximum near x=1,
+ and p_4(x) appears to be a good approximation to f(x) at least until x=2.
+
A table of the derivatives of f(x)=\sqrt{x} evaluated at x=4
diff --git a/ptx/sec_transformations.ptx b/ptx/sec_transformations.ptx
index 8123fee20..4796a64d4 100644
--- a/ptx/sec_transformations.ptx
+++ b/ptx/sec_transformations.ptx
@@ -2142,7 +2142,7 @@
Thus the desired transformation is defined on the rectangle D = [1,4]\times [1,2] and has an inverse given by T^{-1}(x,y) = (y/x,xy).
-
+
The region of integration in
A region in the first quadrant bounded by two hyperbolas, and two lines through the origin.
diff --git a/ptx/sec_trigint.ptx b/ptx/sec_trigint.ptx
index 0c84af962..74d1c8129 100644
--- a/ptx/sec_trigint.ptx
+++ b/ptx/sec_trigint.ptx
@@ -832,7 +832,7 @@
.
-
+ Video solution
diff --git a/ptx/sec_vector_intro.ptx b/ptx/sec_vector_intro.ptx
index 6d8469ef0..5a3dfcd16 100644
--- a/ptx/sec_vector_intro.ptx
+++ b/ptx/sec_vector_intro.ptx
@@ -511,7 +511,7 @@
component-wise.
-
+
Video presentation of (2 videos)
@@ -578,7 +578,7 @@
These are all sketched in .
-
+ Video solution
@@ -771,7 +771,7 @@
(when their initial points are the same).
-
+ Video solution
@@ -1128,7 +1128,7 @@
-
+ Video solution
diff --git a/ptx/sec_vvf.ptx b/ptx/sec_vvf.ptx
index 46ccae9c2..5b7671aaa 100644
--- a/ptx/sec_vvf.ptx
+++ b/ptx/sec_vvf.ptx
@@ -632,7 +632,7 @@
\vec r(t) = \vec p(t) + \vec c(t) = \la \cos(t) + t,-\sin(t) +1\ra,
which is graphed in .
-
+
Further examples with the Fundamental Theorem (4 videos)
-
-
-
The Fundamental Theorem of Line Integrals states that we can determine whether or not \vec F is conservative by determining whether or not \vec F has a potential function.
This can be difficult.
@@ -1477,6 +1472,11 @@
We state this simpler method as a theorem.
+
+
Further examples with the Fundamental Theorem (4 videos)
Illustrating the chain rule, and interpreting as matrix multiplication (see )
+
+
+
Using the Multivariable Chain Rule, Part II
@@ -539,11 +544,6 @@
-
-
diff --git a/ptx/sec_planes.ptx b/ptx/sec_planes.ptx
index 82578d290..afe81794b 100644
--- a/ptx/sec_planes.ptx
+++ b/ptx/sec_planes.ptx
@@ -301,7 +301,7 @@
-
+ Video solution
@@ -373,7 +373,7 @@
it is sketched in .
-
+
Sketching the plane in
@@ -465,7 +465,7 @@
The line and plane are sketched in .
-
+
The line and plane in
@@ -530,7 +530,7 @@
-
+ Video solution
diff --git a/ptx/sec_ratio_root_tests.ptx b/ptx/sec_ratio_root_tests.ptx
index 4c542b3a4..1609ece38 100644
--- a/ptx/sec_ratio_root_tests.ptx
+++ b/ptx/sec_ratio_root_tests.ptx
@@ -269,6 +269,11 @@
and does not work well with terms containing factorials.
+
+
Video presentation of
+
+
+
Root Test
@@ -308,11 +313,6 @@
-
-
Video presentation of
-
-
-
Applying the Root Test
diff --git a/ptx/sec_space_coord.ptx b/ptx/sec_space_coord.ptx
index f77920f3c..44250e449 100644
--- a/ptx/sec_space_coord.ptx
+++ b/ptx/sec_space_coord.ptx
@@ -684,7 +684,7 @@
and is bounded by planes in the y direction.
-
+
@@ -1296,7 +1296,7 @@
-
+ Video solution
diff --git a/ptx/sec_greensthm.ptx b/ptx/sec_greensthm.ptx
index 471f62a06..8bc7aa146 100644
--- a/ptx/sec_greensthm.ptx
+++ b/ptx/sec_greensthm.ptx
@@ -1178,7 +1178,7 @@
that is, find the flux across C and show it is equal to the double integral of \divv \vec F over R.
-
+
The region R used in
A circle in the plane, plotted against a spiral vector field.
diff --git a/ptx/sec_polar.ptx b/ptx/sec_polar.ptx
index 9c6e8f454..99ee3da8e 100644
--- a/ptx/sec_polar.ptx
+++ b/ptx/sec_polar.ptx
@@ -1213,9 +1213,7 @@
and is left as a problem in the Exercise section.
-
-
-
+ Gallery of Polar Curves
diff --git a/ptx/sec_related_rates.ptx b/ptx/sec_related_rates.ptx
index cd8598240..2e5b5da0d 100644
--- a/ptx/sec_related_rates.ptx
+++ b/ptx/sec_related_rates.ptx
@@ -693,7 +693,7 @@
The other driver appears to be speeding slightly.
A table of the derivatives of f(x)=\sqrt{x} evaluated at x=4
diff --git a/ptx/sec_taylor_series.ptx b/ptx/sec_taylor_series.ptx
index 6fb0ffbf8..81eaf9e50 100644
--- a/ptx/sec_taylor_series.ptx
+++ b/ptx/sec_taylor_series.ptx
@@ -611,65 +611,7 @@
which is not particularly good.
- Note that for (1+x)^k, the interval of convergence may contain one or both endpoints,
- depending on the value of k, and we are using the generalized binomial coefficients
-
- \binom{k}{n} = \frac{k(k-1)\cdots (k-(n-1))}{n!}
- .
- Taylor Seriescommon series
-
-
-
-
+ Important Taylor Series Expansions
diff --git a/ptx/sec_triple_int.ptx b/ptx/sec_triple_int.ptx
index d794a35ee..56edeade2 100644
--- a/ptx/sec_triple_int.ptx
+++ b/ptx/sec_triple_int.ptx
@@ -2877,31 +2877,7 @@
-
- Iterated Integration, (Part II)
-
-
- Let D be a closed,
- bounded region in space,
- over which g_1(x), g_2(x), f_1(x,y),
- f_2(x,y) and h(x,y,z) are all continuous,
- and let a and b be real numbers.
-
-
-
- The iterated integral
- \ds \int_a^b\int_{g_1(x)}^{g_2(x)}\int_{f_1(x,y)}^{f_2(x,y)} h(x,y,z)\, dz\, dy\, dx is evaluated as
- integrationtriple
- triple integral
- iterated integration
-
- \int_a^b\int_{g_1(x)}^{g_2(x)}\int_{f_1(x,y)}^{f_2(x,y)} h(x,y,z)\, dz\, dy\, dx = \int_a^b\int_{g_1(x)}^{g_2(x)}\left(\int_{f_1(x,y)}^{f_2(x,y)} h(x,y,z)\, dz\right) dy\, dx
- .
-
-
-
-
-
+ Iterated Integration, (Part II)
From 999f4a763d0179f161e2d32aade2a11c25d9763e Mon Sep 17 00:00:00 2001
From: sean-fitzpatrick
Date: Sat, 6 Jun 2026 13:55:41 -0600
Subject: [PATCH 22/28] no longer need two versions here
---
ptx/sec_taylor_series.ptx | 24 ++++++++++++------------
1 file changed, 12 insertions(+), 12 deletions(-)
diff --git a/ptx/sec_taylor_series.ptx b/ptx/sec_taylor_series.ptx
index 81eaf9e50..a4f1111b1 100644
--- a/ptx/sec_taylor_series.ptx
+++ b/ptx/sec_taylor_series.ptx
@@ -583,7 +583,7 @@
- In
+ In
we give a table of the Taylor series of a number of common functions.
We then give a theorem about the
algebra of power series, that is,
@@ -595,7 +595,7 @@
Before we investigate combining functions,
consider the Taylor series for the arctangent function
- (see ).
+ (see ).
Knowing that \tan^{-1}(1) = \pi/4,
we can use this series to approximate the value of \pi:
@@ -770,13 +770,13 @@
Write out the first 3 terms of the Taylor Series for
- f(x) = e^x\cos(x) using
+ f(x) = e^x\cos(x) using
and .
- informs us that
+ informs us that
e^x = 1+x+\frac{x^2}{2!}+\frac{x^3}{3!}+\cdots \text{ and } \cos(x) = 1-\frac{x^2}{2!}+\frac{x^4}{4!}+\cdots
.
@@ -818,7 +818,7 @@
-
Deriving the Taylor series for \arctan(x) in
+
Deriving the Taylor series for \arctan(x) in
@@ -1125,7 +1125,7 @@
- Using
+ Using
and ,
we recognize f(x) = e^{2x}:
@@ -1141,7 +1141,7 @@
Finding a pattern in the coefficients that match the series expansion of a known function,
- such as those shown in ,
+ such as those shown in ,
can be difficult.
What if the coefficients in the previous example were given in their reduced form;
how could we still recover the function y=e^{2x}?
@@ -1256,7 +1256,7 @@
-
+
gives the nth term of the Taylor series of common functions.
Verify the formula given in the Key Idea by finding
the first few terms of the Taylor series of the given function and identifying a pattern.
@@ -1388,7 +1388,7 @@
Find a formula for the nth term of the Taylor series of f(x),
centered at c,
by finding the coefficients of the first few powers of x and looking for a pattern.
- (The formulas for several of these are found in ;
+ (The formulas for several of these are found in ;
show work verifying these formula.)
@@ -1555,7 +1555,7 @@
Show that the Taylor series for f(x),
- as given in ,
+ as given in ,
is equal to f(x) by applying ;
that is, show \lim\limits_{n\to\infty}R_n(x) =0.
@@ -1743,7 +1743,7 @@
- Use the Taylor series given in to verify the given identity.
+ Use the Taylor series given in to verify the given identity.
@@ -1925,7 +1925,7 @@
- Use the Taylor series given in
+ Use the Taylor series given in
to create the Taylor series of the given functions.
diff --git a/ptx/sec_polarcalc.ptx b/ptx/sec_polarcalc.ptx
index 0b996a578..7198564e6 100644
--- a/ptx/sec_polarcalc.ptx
+++ b/ptx/sec_polarcalc.ptx
@@ -195,7 +195,7 @@
We want the results in [0,2\pi];
we also recognize there are two solutions,
one in the third quadrant and one in the fourth.
- Using reference angles, we have our two solutions as
+ Using reference angles, the two solutions are
\theta =3.39 and 6.03 radians.
The four points we obtained where the limaçon has a horizontal tangent line are given in
with black-filled dots.
diff --git a/ptx/sec_substitution.ptx b/ptx/sec_substitution.ptx
index 4814a53e8..abba76f1f 100644
--- a/ptx/sec_substitution.ptx
+++ b/ptx/sec_substitution.ptx
@@ -754,7 +754,7 @@
In later sections we'll develop techniques for handling rational functions where substitution is not directly feasible.
-
+ Video solution
diff --git a/ptx/sec_taylor_series.ptx b/ptx/sec_taylor_series.ptx
index a4f1111b1..ab49a29ad 100644
--- a/ptx/sec_taylor_series.ptx
+++ b/ptx/sec_taylor_series.ptx
@@ -611,6 +611,8 @@
which is not particularly good.
+
+
Important Taylor Series Expansions
diff --git a/ptx/sec_total_differential.ptx b/ptx/sec_total_differential.ptx
index f74e5fd38..a5b5beff6 100644
--- a/ptx/sec_total_differential.ptx
+++ b/ptx/sec_total_differential.ptx
@@ -57,21 +57,6 @@
-
-
Finding the total differential
@@ -91,6 +76,21 @@
+
+
We can approximate \ddz with dz,
diff --git a/ptx/sec_trigint.ptx b/ptx/sec_trigint.ptx
index 3ecc1a181..699c15ba2 100644
--- a/ptx/sec_trigint.ptx
+++ b/ptx/sec_trigint.ptx
@@ -797,7 +797,7 @@
-
+
Deriving a power reduction formula for secant integrals
@@ -834,7 +834,7 @@
.
-
+ Video solution
diff --git a/ptx/sec_triple_int.ptx b/ptx/sec_triple_int.ptx
index 56edeade2..f3a44f950 100644
--- a/ptx/sec_triple_int.ptx
+++ b/ptx/sec_triple_int.ptx
@@ -2875,7 +2875,7 @@
This leads us to a definition, followed by an example.
-
+ Iterated Integration, (Part II)
diff --git a/ptx/sec_vector_fields.ptx b/ptx/sec_vector_fields.ptx
index 2dece14eb..0ad802e77 100644
--- a/ptx/sec_vector_fields.ptx
+++ b/ptx/sec_vector_fields.ptx
@@ -846,7 +846,7 @@
-
+