Math 1210 - NFOurrier - Nicolas Fourrier

Nov 30, 2010 - You will get zero if any of these happen. 1. Compute the following integrals: (a) / e4 e. 1 x. √ ln(x) dx. (b) / a. 0 x. √ x2 + a2dx. 4 points. Answer.
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MATH 1210 - Section 002

Fall 2010

Quiz 10 Name:

November 30, 2010

Directions: Write legibly, the use of documents is forbidden, giving or receiving aid on this assignement is forbidden. You will get zero if any of these happen.

1. Compute the following integrals: R e4 (a) e √ 1 dx x ln(x) Ra √ (b) 0 x x2 + a2 dx 4 points

Answer R e4 (a) e √ 1 x

(b)

ln(x)

dx =

R4 1

√ u−1/2 du = 2[ u]41 = 2 by setting u = ln(x)

√ Ra √ R 2a2 2 1 3 2 2 x x2 + a2 dx = a2 u1/2 du = [ 13 u3/2 ]2a a2 = 3 (2 2 − 1)a by setting u = x + a 0 R9

f (x)dx = 4, find

R3

Answer Let u = x2 , then du = 2x dx, so

R3

2. If f is continuous and

0

0

0

xf (x2 )dx. 2 points

xf (x2 )dx =

R9 0

f (u)( 21 du) = 12 (4) = 2

3. Water flows from the bottom of a storage tank at a rate of r(t) = 200 − 4t liters per minute, where 0 ≤ t ≤ 50. Find the amount of water that flows from the tank during the first 10 minutes. 4 points

Answer By the net change theorem, the amount of water that flows from the tank during the first 10 R 10 R 10minutes is: r(t)dt = 0 (200 − 4t)dt = 2000 − 200 − 0 = 1800 liters. 0