 Hello, I am welcome to the session. I am Deepika here. Let's discuss a question which says evaluate the following definite integral integral from 0 to pi by 2 cos square x dx. Now in this question we will use the second fundamental theorem of integral calculus. So let's start the solution. This is equal to integral from 0 to pi by 2 cos square x. Now we will first evaluate the indefinite integral cos square x is equal to square x minus 1. Therefore it is equal to 1 plus cos 2x upon 2. This is equal to 1 by 2 1 plus cos 2 is equal to 1 by 2 into is equal to x by 2 upon 4. Now function cos square x the second fundamental theorem is equal to is equal to 2 pi by 2 by 4 sin equal to this is equal to pi by 4. Now the other question is pi by 4. The solution is clear to you. Bye and take care.