Question

Help please
photo attached.

Answer 1

did you try , u= sin x ?
du=... ?

Answer 2

how do you predict du?
I thought u is the whole equation of the problem.. I have been asking this to people but i am still confused.

Answer 3

predict du ?
i am not sure what you are asking...
when we do substitution, we change the variable completely, so we need to find dx in terms of du also. (dx can't still be there)

Answer 4

ok. du is cosx?

Answer 5

du = cos x dx

Answer 6

so you get \(\int 9u^2 du\)
i am pretty sure you can solve this.

Answer 7

Ok! 9sinx^2cosx?

Answer 8

what ?

Answer 9

\(\int 9u^2du = (9/3)u^3+c = 3\sin^3 x+c\)
because u =sin x
got this ?

Answer 10

Oh I see. so first, I need to set the equation then antiderivative?

Answer 11

where du go?

Answer 12

du or dx does after integrating....and a constant gets added.....

Answer 13

*goes