Skip to Content

Integral of cosine cubed

Home | Calculus 2 | Trigonometric Integrals | Integral of cosine cubed

cos3xdx\displaystyle \int cos^3x \, dx

For this integral, you're dealing with the cosine function raised to the third power, which introduces a bit more complexity. The key to solving problems like this is to break the function down into something more manageable using trigonometric identities.

One common technique involves splitting the cosine cubed into a product of cosine and cosine squared. Once you've done that, the cosine squared can be rewritten using a power-reduction identity, which expresses it in terms of a simpler trigonometric function. By applying this identity, the original integral simplifies into one part that can be integrated directly and another part that requires substitution.

After splitting up the terms and integrating, the result combines the effects of trigonometric manipulation and substitution. This process is typical when working with integrals of odd powers of sine or cosine functions, where breaking down the function helps reduce it to a more solvable form.

Posted by grwgreg a month ago

Related Problems

Evaluate the integral 0π/2cost1+sin2tdt\displaystyle \int_{0}^{\pi/2} \frac{\cos t}{\sqrt{1 + \sin^2 t}} \, dt.

Evaluate cos2(θ)dθ\displaystyle \int \cos^2(\theta) \, d\theta using the double angle identity.

Evaluate the integral of 11x2\frac{1}{\sqrt{1-x^2}} which is equivalent to the inverse sine of x.

Solve sin3xcos4xdx\displaystyle \int \sin^3 x \cos^4 x \, dx using the substitution method where the power of sine is odd.