MAT 127 Midterm: mt2sols09
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April 3, 2009: (30 pts) compute the following integrals. Z sec2 d = tan + c. Z cos3(x) sin4(x)dx = z cos2(x) sin4(x) cos(x)dx = z (1 sin2(x)) sin4(x) cos(x)dx. = z (1 u2)u4du = z (u4 u6)du = u5. 2: (20 pts) griswald puts a frozen hot dog into a pot of boiling water. The temperature of the hot dog at time t = 0 is 0 c. After 2 minutes, the hot dog is 5 c. (a) by newton"s law of cooling, the rate of change of the temperature of the hot dog is proportional to the di erence in temperature between the water and the hot dog. We let y = y(t) denote the temperature at time t. dy dt. = k(100 y), y(0) = 0, y(2) = 5. (b) solve the ivp to obtain the temperature of the hot dog at time t. 100 y dy = k dt = z.