1 / | | /x\ | x*a*sin|-| dx | \a/ | / 0
Integral((x*a)*sin(x/a), (x, 0, 1))
Use integration by parts:
Let and let .
Then .
To find :
Let .
Then let and substitute :
The integral of a constant times a function is the constant times the integral of the function:
The integral of sine is negative cosine:
So, the result is:
Now substitute back in:
Now evaluate the sub-integral.
The integral of a constant times a function is the constant times the integral of the function:
Let .
Then let and substitute :
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 substitute back in:
So, the result is:
Now simplify:
Add the constant of integration:
The answer is:
/ | | /x\ 3 /x\ 2 /x\ | x*a*sin|-| dx = C + a *sin|-| - x*a *cos|-| | \a/ \a/ \a/ | /
/ 2 /1\ /1\\ a*|a *sin|-| - a*cos|-|| \ \a/ \a//
=
/ 2 /1\ /1\\ a*|a *sin|-| - a*cos|-|| \ \a/ \a//
a*(a^2*sin(1/a) - a*cos(1/a))
Use the examples entering the upper and lower limits of integration.