3 / | | 2 | cos(3*x)*sin (x) dx | / 1
Integral(cos(3*x)*sin(x)^2, (x, 1, 3))
Rewrite the integrand:
Integrate term-by-term:
The integral of a constant times a function is the constant times the integral of the function:
Rewrite the integrand:
There are multiple ways to do this integral.
Let .
Then let and substitute :
Integrate term-by-term:
The integral of a constant times a function is the constant times the integral of the function:
The integral of is when :
So, the result is:
The integral of is when :
The result is:
Now substitute back in:
Rewrite the integrand:
Integrate term-by-term:
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 is when :
Now substitute back in:
So, the result is:
Let .
Then let and substitute :
The integral of is when :
Now substitute back in:
The result is:
Rewrite the integrand:
Integrate term-by-term:
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 is when :
Now substitute back in:
So, the result is:
Let .
Then let and substitute :
The integral of is when :
Now substitute back in:
The result is:
So, the result is:
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 is when :
Now substitute back in:
So, the result is:
The result is:
Now simplify:
Add the constant of integration:
The answer is:
/ | 5 3 | 2 4*sin (x) sin (x) | cos(3*x)*sin (x) dx = C - --------- + ------- | 5 3 /
2 2 2 2 7*sin (1)*sin(3) 2*cos (3)*sin(9) 2*cos (1)*sin(3) 7*sin (3)*sin(9) 2*cos(1)*cos(3)*sin(1) 2*cos(3)*cos(9)*sin(3) - ---------------- - ---------------- + ---------------- + ---------------- - ---------------------- + ---------------------- 15 15 15 15 5 5
=
2 2 2 2 7*sin (1)*sin(3) 2*cos (3)*sin(9) 2*cos (1)*sin(3) 7*sin (3)*sin(9) 2*cos(1)*cos(3)*sin(1) 2*cos(3)*cos(9)*sin(3) - ---------------- - ---------------- + ---------------- + ---------------- - ---------------------- + ---------------------- 15 15 15 15 5 5
Use the examples entering the upper and lower limits of integration.