Homework # 9 - Math 149
The problems on this homework must be done alone. The honor code is in effect.
First name: Last name:
For problems 1 - 4, consider the function $$f(x) = \left\{ \begin{array}{ll} x-1 \hspace{.1 in} & \mbox{if } x \leq 2 \\ x+1 & \mbox{if } x>2\end{array}\right.$$
1. Take the derivative of \(f(x) = \frac{1}{x^2}\).
a. \(f'(x) = \frac{-2}{x}\)
b. \(f'(x) = \frac{2}{x}\)
c. \(f'(x) = \frac{2}{x^3}\)
d. \(f'(x) = \frac{-2}{x^3}\)
e. \(f'(x) = 0\)
2. Take the derivative of \(f(x) = 3x^2 - 5x + 10\).
a. \(f'(x) = 6x - 5\)
b. \(f'(x) = 3x - 5\)
c. \(f'(x) = 2x^2 - 5x\)
d. \(f'(x) = 2x^2 - 5\)
e. \(f'(x) = 2x^2 - 4x + 10\)
3. Take the derivative of \(g(x) = 2^{-100}\).
a. \(g'(x) = (100) 2^{101}\)
b. \(g'(x) = (-100) 2^{-101}\)
c. \(g'(x) = (100) 2^{99}\)
d. \(g'(x) = (-100) 2^{-99}\)
e. \(g'(x) = 0\)
4. Differentiate (that means take the derivative) \(f(x) = \sqrt{x} \sin x\)
a. \( f'(x) = \frac{\cos x}{2\sqrt{x}}\)
b. \( f'(x) = \frac{\sin x}{2\sqrt{x}}\)
c. \( f'(x) = \frac{1}{2\sqrt{x}} + \cos x\)
d. \( f'(x) = \sqrt{x}\cos x + \frac{1}{2\sqrt{x}} \sin x\)
e. \( f'(x) = \frac{1}{2\sqrt{x}} \cos x + \sqrt{x}\sin x\)
5. Differentiate \(g(x) = \frac{2^x + 5}{x}\)
a. \( g'(x) = x 2^x - 1\)
b. \( g'(x) = \frac{x^2 2^{x-1}-2^x - 5}{x^2}\)
c. \( g'(x) = \frac{2^x + 5 - x2^{x-1}}{x^2}\)
d. \( g'(x) = (\ln 2)2^x\)
e. \( g'(x) = \frac{(\ln 2)x2^x - 2^x - 5}{x^2}\)
6. Differentiate\(g(x) = x^e\)
a. \( g'(x) = (\ln x) x^e\)
b. \( g'(x) = e x^{e-1}\)
c. \( g'(x) = x^e\)
d. \( g'(x) = x^{e+1}\)
e. \( g'(x) = (\ln e) x^e\)
7. Which of the following limits represents the slope of the tangent line to the curve \(y = f(x) = x^2\) at \(x = 2\)?
a. \(\lim_{h \rightarrow 0} \frac{ 2+h^2 - 2^2}{h}\)
b. \(\lim_{h \rightarrow 0} \frac{ (2+h)^2 - 2^2}{h}\)
c. \(\lim_{h \rightarrow 0} \frac{ 1+h^2 - 2^2}{h}\)
d. \(\lim_{h \rightarrow 0} \frac{ (1+h)^2 - 1^2}{h}\)
e. \(\lim_{h \rightarrow 0} \frac{ (1+h)^2 - h^2}{h}\)
8. If \(f(x) = 2^x\), find \(f^{(10)}(x)\).
a. \(f^{(10)}(x)= (\ln 2)^{10} 2^x\)
b. \(f^{(10)}(x)= x 2^{x-1}\)
c. \(f^{(10)}(x)= (x)(x-1)\ldots(x-9) 2^{x-10}\)
d. \(f^{(10)}(x)= (x)(x-1)\ldots(x-10) 2^{x-10}\)
e. \(f^{(10)}(x)= (\ln 2)^{9} 2^x\)