Question
Please help me with attched
Consider the following graph of f(x) = x2 + 1: Assume that the area under the curve from 0 to b is three times that of the area from 0 to a, that is assume that What is the relationship between a and b? Suppose that a = 1. Compute or approximate b. If you choose to approximate it, make sure that your approximation is accurate to three decimal places. Meet 1/xlnx: Compute the area under f (x) = 1/xlnx from x = 1.01 to 1.0201, from 4 to 16, and from 10 to 100. What do the three pairs of endpoints have in common?
Explanation / Answer
1)
int f(x) dx = 1/3 x^3 + x
So we want to have:
1/3 b^3 + b = 3(1/3 a^3 + a)
or
b^3 + 3b = 3a^3 + 9a
b)
a=1 -> b^3 + 3b = 12
b^3 + 3b - 12 = 0
-> b = 1.859