pi -- 4 / | | 2 ___ | x *\/ 2 *cos(x) dx | / 0
Integral((x^2*sqrt(2))*cos(x), (x, 0, pi/4))
Use integration by parts:
Let and let .
Then .
To find :
The integral of cosine is sine:
Now evaluate the sub-integral.
Use integration by parts:
Let and let .
Then .
To find :
The integral of sine is negative cosine:
Now evaluate the sub-integral.
The integral of a constant times a function is the constant times the integral of the function:
The integral of cosine is sine:
So, the result is:
Now simplify:
Add the constant of integration:
The answer is:
/ | | 2 ___ ___ ___ 2 ___ | x *\/ 2 *cos(x) dx = C - 2*\/ 2 *sin(x) + \/ 2 *x *sin(x) + 2*x*\/ 2 *cos(x) | /
/ ___ ___ 2\ ___ | ___ pi*\/ 2 \/ 2 *pi | \/ 2 *|- \/ 2 + -------- + ---------| \ 4 32 /
=
/ ___ ___ 2\ ___ | ___ pi*\/ 2 \/ 2 *pi | \/ 2 *|- \/ 2 + -------- + ---------| \ 4 32 /
sqrt(2)*(-sqrt(2) + pi*sqrt(2)/4 + sqrt(2)*pi^2/32)
Use the examples entering the upper and lower limits of integration.