 Hi and welcome to the session. I am Deepika here. Let's discuss a question. If cot theta is equal to 7 upon 8 evaluate part 1 1 plus sin theta into 1 minus sin theta upon 1 plus cos theta into 1 minus cos theta and part 2 cot square theta. Now we know that according to the Pythagoras theorem, this is a right angle ABC. So according to the Pythagoras theorem we have AC square is equal to AB square plus BC square, hypotenuse square is equal to some of the squares of other two sides and theta is equal to addition to angle theta upon side opposite to angle theta that is BC upon AB sin theta is equal to side opposite to angle theta upon hypotenuse that is AB upon AC and cos theta is equal to side adjacent to angle theta upon hypotenuse that is BC upon AC. So this is a key idea behind our question. We will take the help of this key idea to solve the above question. So let's start the solution part 1. Have given cot theta is equal to BC upon AB is equal to equal to 7k then AB is equal to any positive number equal to 7k and AB is equal to 8k. Let us find out AC by using Pythagoras theorem. So by using Pythagoras theorem is equal to AB square plus BC square that is AC square is equal to 8k square plus 7k square this implies AC square is equal to 64k square plus 49k square and again this implies AC square is equal to 114k square AC is equal to that is 8k which is equal to 8k is equal to 1 minus sin square theta minus cos square theta is equal to 8 upon under root 113 square upon under root 113 square. So this is equal to 1 minus 6413 upon 49 over 113. So this is equal to 113 minus 64 upon 113 into 113 upon 113 minus 49. So this is equal to 49 64 1 plus sin theta into 1 minus sin theta upon 1 plus cos theta into 1 minus cos theta is equal to 49 upon 64. Hence the answer for part 1 is 49 upon 64. So let us move to the part 2 this is equal to now BC square upon so this is equal to 49k square upon 64k square and this is again equal to 49 upon 64. Hence the answer for part 2 is that is cos square theta is equal to 49 upon 64. I hope the question is clear to you. Bye and take care.