How do you find the antiderivative of int 1/(3x-7)^2 dx from [3,4]?

1 Answer
Dec 6, 2016

We can rewrite this as

int(3x - 7)^-2dx

We let u = 3x - 7, then du = 3(dx), and dx = (du)/3.

=>int_3^4(u)^-2(1/3)du

=>1/3int_3^4(u)^-2du

=>1/3(-1/2u^-1)|_3^4

=>-1/(6u)|_3^4

=>-1/(6(3x- 7))|_3^4

=>-1/(18x - 42)|_3^4

We now evaluate using int_a^b(f(x)) = F(b) - F(a), where F(x) is the antiderivative of f(x).

=>-1/(18(4) - 42) - (-1/(18(3) - 42))

=>-1/30 + 1/12

=>1/20

Hopefully this helps!