Thread: Question

Looking at some of the older stuff and for ∫1/10(x)(6x^2-15) dx became 1/120 ∫12x(6x^2-15) dx, how was the 1/120 ∫12x arrived at?

1/10 = 1/120 * 12
and we know that you can move a constant outside of the integral

I can see that but why 12?

probably to make u-substitution more straightforward

i.e.
u=6x^2-15
du=12x dx

Not sure if I quite get it but thanks

EDIT:
1/120 ∫12x(6x^2-15) dx
=1/120 ∫ 72x^3-180x dx


I'm sorry i forgot that it was possible that you didn't cover u-substitution, which is just a method of integration and all you had to do was multiply it out and integrate the polynomial! sorry!
and 1/120 was probably to avoid fractions during integration

Thanks for that I have to get used to such manipulation, I have never been on one of these forums before and can not figure out how to do a smiley face

Originally Posted by landmark

Thanks for that I have to get used to such manipulation, I have never been on one of these forums before and can not figure out how to do a smiley face

The usual way: = : + )

-Dan