M161, Midterm 1, Fall 2010 Problem Points Score 1 20

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M161, Midterm 1, Fall 2010

Problem Points Score

1 20

Name:

2 15

Section:

Instructor:

Time: 75 minutes. You may not use calculators or other electronic devices on this exam

3

4

5

X

20

25

20

100 d sin( x ) = cos( x ) , dx d dx asin( x ) = √

1

1 − x 2 d dx sin(2 tan

, acsc( x ) = −

1 x

√ x 2 − 1

2 x ) = 2 sin( x ) cos(

( x ) + 1 = sec 2 ( x ) x )

, d d cos( x ) = − sin( x ) , dx d dx acos( x ) = −

1

1 − x 2

, dx

Z asec( x ) = x

√ x 2 − 1

, ln xdx = x ln x − x + C cos 2 ( x ) =

1 + cos(2 x )

2

1 d tan( x ) = sec

2

( x ) , dx d dx atan( x ) =

1

1 + x 2

, d sec( x ) = sec( x ) tan( x ) , dx

Z sec( x ) dx = ln | sec( x ) + tan( x ) | + C sin

2

( x ) =

1 − cos(2 x )

2

Theorem (The Derivative Rule for Inverses) If f has an interval I as domain and f

0

( x ) exists and is never zero on I , then f

− 1 is differentiable at every point in its domain. The value of ( f point a = f

− 1

)

0

− 1 at a point b in the domain of f

− 1

( b ): ( f

− 1

)

0

( b ) = f 0 ( f

1

− 1 ( b ))

.

is the reciprocal of the value of f

0 at the

1. These are short answer questions. Put your answer in the box. No work outside the box will be graded.

(a) What does asin(

3 / 2) equal?

(b) Suppose that y = g ( x ) is a differentiable function that has an inverse. Suppose that the graph of g ( x ) passes through the origin with slope 2. What is the slope of the inverse function g

− 1 ( x ) at the origin?

(c) What is the derivative of ln(5x) − ln(7x)?

(d) What is the domain of the function atan(3 x )?

2. The first list contains 7 statements (5 correct and 2 false). The second list contains 5 reasons (labeled A − E ) why the correct statements are true. In the box next to each false statement, write the letter F . Match each correct statement with the reason why it is true, and write the letter in the box.

Statements: ln(e x

) = x.

ln(e) = 1.

d dx

(ln(x)) =

1 x

.

ln(x) is one − to − one.

ln(

1 x

) =

1 ln(x)

.

ln(x) =

Z x

1 dt

.

t ln(x) is concave up.

Reasons:

(A) by the Definition of the Natural Logarithm Function.

(B) by the Definition of the Number e .

(C) by the Fundamental Theorem of Calculus.

(D) because 1 /x is positive for all x > 0.

(E) by the Definition of the Natural Exponential Function.

3. Evaluate the following integrals. Show all your work.

(a)

Z sin

3

( x ) · cos

2

( x ) dx .

(b)

Z dx

6 x − 3 x 2

.

4. Let f ( x ) = e 2 x − 2

(a) State the domain and range of f ( x ).

(b) Explain why f ( x ) has an inverse, without computing what the inverse is.

(c) Find a formula for f

− 1 ( x ), and state the domain and range of f

− 1 ( x )

(d) Graph f ( x ) and f

− 1

( x ).

5. The following differential equation fulfills the initial value condition y (1) = − 1 / 3: e

− x

3

+1 dy dx

= 3 x

2 y

2

.

(a) Show that the differential equation is separable.

(b) Solve the differential equation. In other words, solve for y as a function of x and an integration constant C .

(c) Determine the integration constant C that fulfills the condition y (1) = − 1 / 3.

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