00:01
Hi, here for the given question we are given that r is equal to 1 plus cos theta and r is equal to 3 cos theta.
00:08
So here in our case, this is the graph.
00:10
Now we need to calculate the area.
00:12
So first of all, we will find the limit.
00:13
So we have 1 plus cos theta equals to 3 cos theta.
00:17
So we have 1 is equal to 2 cos theta and here we have cos theta equals to 1 by 2.
00:24
So theta will be equal to pi by 3.
00:26
So here area can be calculated as integration over 0 to pi and integration over 0 to r, which is equal to 3 cos theta and r dr d theta over here.
00:40
So simplifying further, here it is limit pi by 3.
00:44
Now area can be written as 2 times of integration over 0 to here it is from 1 plus cos theta.
00:52
So 2 times integration over 0 to pi by 3.
00:56
Here it is from minus pi by 3 to pi by 3 because of the limit.
01:00
So 2 times here we have 1 plus cos theta and here 3 cos theta r dr d theta.
01:07
Now further integrating with respect to d theta, first of all, so area equals to 2 times integration over 0 to pi by 3 and here r will be as r square upon 2 and here we have 1 plus cos theta 3 times of cos theta and here we have d theta.
01:25
So substituting the value of the limit, we have integration over 0 to pi by 3.
01:29
Here it is 2 times 1 by 2 and here we have 9 cos square theta minus 1 plus cos theta whole square d theta.
01:38
Now we know that if we simplify this bracket and solve further, we have area equals to integration over 0 to pi by 3 9 times cos square theta.
01:48
It will be 8 times cos square theta minus 2 cos theta minus 1 d theta...