Suppose that in a memory experiment the rate of memorizing is given by M ' ( t ) = − 0.007 t^2 + 0.8 t , where M ' ( t ) is the memory rate, in words per minute.

Question

 How many words are memorized in the first 12 minutes?

Hint:Round your answer to the nearest whole word.

Answer 1

M'(t) = 0.007t^2 + 0.8t

M(t) = [(.007)/3]t^3 + 0.4t^2

M(12) = (.007)576 + 0.4(12)^2

= 4.032 + 57.6= 61.632 = 62 words, rounded off