Learn how to solve definite integrals problems step by step online. Integrate the function cos(3x)cos(4x) from 0 to pi/4. Simplify \cos\left(3x\right)\cos\left(4x\right) into \frac{\cos\left(7x\right)+\cos\left(-x\right)}{2} by applying trigonometric identities. Take the constant \frac{1}{2} out of the integral. Expand the integral \int\left(\cos\left(7x\right)+\cos\left(-x\right)\right)dx into 2 integrals using the sum rule for integrals, to then solve each integral separately. Apply the formula: \int\cos\left(ax\right)dx=\frac{1}{a}\sin\left(ax\right)+C, where a=7.

Integrate the function cos(3x)cos(4x) from 0 to pi/4