Question

integral of cos4x

Answer 1

Is it
\[\int\limits \cos (4 x) \, dx\]

Answer 2

\[a= \pi/8 b= \pi/4 and everything else you wrote is correct. thank you\]

Answer 3

a=π/8 and b=π/4 ... and everything else you wrote was correct. sorry about spacing last message

Answer 4

Just direct aprroach, use substitution
u=4x
du=4dx
\[\frac{du}{4}=dx\]
\[=\frac{1}{4} \int\limits \cos u \, du\]
\[=\frac{ \sin u }{4}\]
\[\huge[\frac{1}{4} \sin(4 x)]_{\pi /8}^ {\pi/4}\]

Answer 5

Then finish it up by substituting it in, you following?