Question

you want to evaluate the integral xsin(5x^2)dx using substituiton.
which of the following is the best choice for the substitution variable u?

A. u=3x-x^3
B. u=4x^2
C.(3x-x^3)^5
D. x^2(3x-x^3)^5

Answer 1

Do you have any questions on the method of substitution?

Answer 2

u= xsin(5x^2)
u= sin(5x^2)
u= x
u= 5x^2
i got u= sin(5x^2).....

Answer 3

The derivative of 5x^2 is 10x, so try sin(u) du.

Answer 4

Let u=5x^2 then see what you need to do to get from dx to du.