 Hi and welcome to the session. I am Asha and I am going to help you with the following question which says, prove the following and we have sin n plus 1 into x into sin n plus 2 into x plus cos n plus 1 into x into cos n plus 2 into x is equal to cos x. So, let us begin with the solution and we will start with the left hand side of the problem and show that it is equal to cos x. So, left hand side is sin n plus 1 into x into sin n plus 2 into x plus cos n plus 1 into x into cos n plus 2 into x. So, let n plus 1 into x be equal to a and n plus 2 into x is equal to b. Then left hand side can be written as sin a into sin b plus cos a into cos b. Now, let us learn one identity which says sin a sin b plus cos a cos b is equal to cos a minus b. So, with the help of this identity L it is further becomes cos of a minus b which is further equal to cos a is n plus 1 into x then we have minus b is n plus 2 into x. So, this is further equal to cos n x plus x minus n x minus 2 x. So, this is further equal to cos plus n x cancels out with minus n x and we have x minus 2 x which is equal to cos minus x which is further equal to cos x which is the right hand side of the given problem. Thus we have sin n plus 1 into x into sin n plus 2 into x plus cos n plus 1 into x into cos n plus 2 into x is equal to cos x. So, this completes the solution. Hope you enjoyed it. Take care and have a good day.