@@ -40,6 +40,7 @@ functions that are hard to expand!
4040
41411 . $f(x) = (x+1)(2x^2 + 5)(5x^3-4)$
4242
43+ ``` {solution}
4344 Identify:
4445
4546 \begin{equation}
@@ -67,9 +68,11 @@ functions that are hard to expand!
6768 &+ (2x^2+5)(5x^3-4)
6869 \end{align}
6970 <!--markdownlint-enable MD011 -->
71+ ```
7072
71732 . $f(x) = \dfrac{1}{x} e^x$
7274
75+ ``` {solution}
7376 Identify:
7477
7578 \begin{align}
@@ -83,9 +86,11 @@ functions that are hard to expand!
8386 f'(x) &= \frac{1}{x}e^x + e^x(-\frac{1}{x^2}) \\
8487 &= e^x\left(\frac{1}{x} - \frac{1}{x^2}\right)
8588 \end{align}
89+ ```
8690
87913 . $f(x) = (x^2+3)\ln x$
8892
93+ ``` {solution}
8994 Identify:
9095
9196 \begin{align}
@@ -99,6 +104,7 @@ functions that are hard to expand!
99104 f'(x) &= (x^2+3)\cdot\frac{1}{x} + (\ln x)(2x) \\
100105 &= \frac{x^2+3}{x} + 2x\ln x
101106 \end{align}
107+ ```
102108
103109## Quotient Rule
104110
@@ -143,6 +149,7 @@ is helpful to do the quotient rule!
143149
1441501 . $\displaystyle f(x) = \frac{x^2 -1}{x^4 + 2}$
145151
152+ ``` {solution}
146153 \begin{align}
147154 u &= x^2 -1 & v &= x^4 +2 \\
148155 u' &= 2x & v' &= 4x^3
@@ -154,9 +161,11 @@ is helpful to do the quotient rule!
154161 f'(x) &= \frac{ (x^4 + 2) \cdot (2x) - (x^2 - 1) \cdot (4x^3)}{(x^4 +2)^2}\\
155162 &= \frac{2x^5 + 4x^2 - 4x^5 +4x^3}{x^8 + 2x^4 + 4}
156163 \end{align}
164+ ```
157165
1581662 . $\displaystyle f(x) = \frac{e^{x}}{1 + x}$
159167
168+ ``` {solution}
160169 \begin{align}
161170 u &= e^{x} & v &= 1 + x \\
162171 u' &= e^{x} & v' &= 1
@@ -168,9 +177,11 @@ is helpful to do the quotient rule!
168177 f'(x) &= \frac{(1 + x) \cdot e^{x} - e^{x} \cdot 1}{(1 + x)^2} \\
169178 &= \frac{x e^{x}}{(1 + x)^2}
170179 \end{align}
180+ ```
171181
1721823 . $\displaystyle f(x) = \frac{(x - 1)(x^2 - 2x)}{x^4}$
173183
184+ ``` {solution}
174185 \begin{align}
175186 u &= & v &= x^4\\
176187 u' &= 3x^2 - 6x + 2 & v' &= 4x^3 \\
@@ -187,6 +198,7 @@ is helpful to do the quotient rule!
187198 Note, though, that in this case we could also have expanded the numerator,
188199 divided through by $x^8$, and differentiated term-by-term to arrive at the
189200 same answer. The faster route depends on the problem!
201+ ```
190202
191203## Chain rule
192204
@@ -225,6 +237,7 @@ The results match! Some additional examples:
225237
2262381 . $f(x) = e^{x^2}$
227239
240+ ``` {solution}
228241 Make the replacement $u = x^2$:
229242
230243 \begin{align}
@@ -237,9 +250,11 @@ The results match! Some additional examples:
237250 \begin{equation}
238251 f'(x) = \dd{}{f}{u} \dd{}{u}{x} = e^{u} \dd{}{u}{x} = e^{x^2} \cdot 2x
239252 \end{equation}
253+ ```
240254
2412552 . $f(x) = \ln(1 + 2x)$
242256
257+ ``` {solution}
243258 Make the replacement $u = 1+2x$:
244259
245260 \begin{align}
@@ -252,9 +267,11 @@ The results match! Some additional examples:
252267 \begin{equation}
253268 f'(x) = \dd{}{f}{u} \dd{}{u}{x} = \frac{1}{u} \dd{}{u}{x} = \frac{2}{1 + 2x}
254269 \end{equation}
270+ ```
255271
2562723 . $f(x) = \dfrac{2}{1 + 2x}$
257273
274+ ``` {solution}
258275 Make the replacement $u = 1+2x$:
259276
260277 \begin{align}
@@ -268,6 +285,7 @@ The results match! Some additional examples:
268285 f'(x) = \dd{}{f}{u} \dd{}{u}{x} = -2u^{-2} \cdot \dd{}{u}{x} =
269286 \frac{-4}{(1 + 2x)^2}
270287 \end{equation}
288+ ```
271289
272290## Trigonometric functions
273291
@@ -361,8 +379,6 @@ The roots occur at $t = T/4$ or $3T/4$, when $x = 0$ and the spring is no longer
361379stretched. All potential energy has been converted to kinetic energy!
362380````
363381
364- ## Skill builder problems
365-
3663821 . $f(x) = 3 \cos x + \sin x$
367383
368384 ``` {solution}
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