How Do You Integrate sin^6(x) Using Trigonometric Identities?

In summary, the problem is to find the integral of sin^6 x dx. The progress so far has been to rewrite it as \frac 1 8 \int (1 - 3cos2x + 3cos^22x - cos^32x) dx, using a half angle identity for cos^2(2x). The next step is to use a sine integral reduction formula to simplify the integral further. Once you get to sin^0(x), the integral will be easy to solve.
  • #1
Stevecgz
68
0
Problem:
[tex]\int sin^6 x dx[/tex]
Progress so far:
[tex]\int (sin^2 x)^3 dx[/tex]
[tex]\frac{1}{8} \int (1-cos2x)^3 dx [/tex]
[tex]\frac 1 8 \int (1 - 3cos2x + 3cos^22x - cos^32x) dx[/tex]

Any help is appreciated.

I can see using a half angle identity for cos^2(2x), but what do I do with the cos^3(2x)?


Steve
 
Last edited:
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  • #2
Try looking up some sine integral reduction formulas on google. They take care of integrals involving powers of sine pretty nicely.
 
  • #3
whozum said:
Try looking up some sine integral reduction formulas on google. They take care of integrals involving powers of sine pretty nicely.

I've found one in my text. Would I simply continue using the reduction formula until I get to sin^0(x)?

Steve
 
  • #4
Yes that's pretty much how we did it.
 
  • #5
Thanks whozum.

Steve
 

FAQ: How Do You Integrate sin^6(x) Using Trigonometric Identities?

What is a trigonometric integral?

A trigonometric integral is an integral that involves trigonometric functions, such as sine, cosine, tangent, etc. It is used to find the area under a curve that contains trigonometric functions.

How do you solve a trigonometric integral?

To solve a trigonometric integral, you can use integration techniques such as substitution, integration by parts, or trigonometric identities. It is also helpful to have a good understanding of basic trigonometric functions and their derivatives.

What are the common applications of trigonometric integrals?

Trigonometric integrals are commonly used in physics, engineering, and other fields to solve problems involving periodic or oscillating functions. They are also used in calculating areas, volumes, and arc lengths in curved shapes and surfaces.

Can trigonometric integrals be solved using a calculator?

Yes, trigonometric integrals can be solved using a graphing calculator or a computer program that has integration capabilities. However, it is important to have a good understanding of the concepts and techniques involved in solving trigonometric integrals to ensure accurate results.

Are there any special cases or exceptions when solving trigonometric integrals?

Yes, there are some special cases and exceptions when solving trigonometric integrals. For example, if the integrand contains a radical expression, the substitution method may be needed. Also, if the integrand contains both even and odd powers of trigonometric functions, certain trigonometric identities may need to be used to simplify the integral.

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