## Step-by-step Solution

Problem to solve:

Solving method

Learn how to solve calculus problems step by step online.

$\displaystyle\int u\cdot dv=u\cdot v-\int v \cdot du$

Learn how to solve calculus problems step by step online. Find the integral int(x*cos(x))dx. We can solve the integral \int x\cos\left(x\right)dx by applying integration by parts method to calculate the integral of the product of two functions, using the following formula. First, identify u and calculate du. Now, identify dv and calculate v. Solve the integral.