Question

Find f(x) if f'(x) = 3cos(x/4) and f(pi) = 9 sqrt(2)

Answer 1

did you find the anti derivative?

Answer 2

i know the answer:
\[3\sqrt{2} + 12 \sin (\frac{x}{8}) + c\]
but i only went as far as:
\[12 \sin (\frac{x}{8})\]
and I can't figure out where the \[3\sqrt2\] came from

Answer 3

Are you sure that's the answer?

Answer 4

So if you want f(x) given f'(x) then you know it within a constant of integration.

f(x)=12sin(x/4)+C

not divided by 8 on the inside. From there you can plug in x=pi and f(pi)=9sqrt(2) to solve for C.

Answer 5

tried that but it didn' work out
where does the \[3\sqrt2\] come from
thats the problem