Integral of 1/(sinx)^4 dx
The solution
Detail solution
-
Rewrite the integrand:
csc4(x)=(cot2(x)+1)csc2(x)
-
There are multiple ways to do this integral.
Method #1
-
Let u=cot(x).
Then let du=(−cot2(x)−1)dx and substitute du:
∫(−u2−1)du
-
Integrate term-by-term:
-
The integral of a constant times a function is the constant times the integral of the function:
∫(−u2)du=−∫u2du
-
The integral of un is n+1un+1 when n=−1:
∫u2du=3u3
So, the result is: −3u3
-
The integral of a constant is the constant times the variable of integration:
∫(−1)du=−u
The result is: −3u3−u
Now substitute u back in:
−3cot3(x)−cot(x)
Method #2
-
Rewrite the integrand:
(cot2(x)+1)csc2(x)=cot2(x)csc2(x)+csc2(x)
-
Integrate term-by-term:
-
Let u=cot(x).
Then let du=(−cot2(x)−1)dx and substitute −du:
∫(−u2)du
-
The integral of a constant times a function is the constant times the integral of the function:
∫u2du=−∫u2du
-
The integral of un is n+1un+1 when n=−1:
∫u2du=3u3
So, the result is: −3u3
Now substitute u back in:
−3cot3(x)
-
∫csc2(x)dx=−cot(x)
The result is: −3cot3(x)−cot(x)
Method #3
-
Rewrite the integrand:
(cot2(x)+1)csc2(x)=cot2(x)csc2(x)+csc2(x)
-
Integrate term-by-term:
-
Let u=cot(x).
Then let du=(−cot2(x)−1)dx and substitute −du:
∫(−u2)du
-
The integral of a constant times a function is the constant times the integral of the function:
∫u2du=−∫u2du
-
The integral of un is n+1un+1 when n=−1:
∫u2du=3u3
So, the result is: −3u3
Now substitute u back in:
−3cot3(x)
-
∫csc2(x)dx=−cot(x)
The result is: −3cot3(x)−cot(x)
-
Add the constant of integration:
−3cot3(x)−cot(x)+constant
The answer is:
−3cot3(x)−cot(x)+constant
The answer (Indefinite)
[src]
/
| 3
| 1 cot (x)
| ------- dx = C - cot(x) - -------
| 4 3
| sin (x)
|
/
∫sin4(x)1dx=C−3cot3(x)−cot(x)
The graph
Use the examples entering the upper and lower limits of integration.