 Hello friends, welcome to the session I am Valka, let us discuss the question that is differentiate with respect to x, the function in exercise is 1 to 11, our given function is cos a cos x plus b sin x for some constant a and v. Let us start with the solution, let y equal to cos a cos x plus b sin x. Now we differentiate both sides with respect to x, we differentiate both sides with respect to x by chain rule, we get dy by dx equal to minus sin a cos x plus b sin x into dy dx of a cos x plus b sin x. This implies dy by dx equal to minus sin a cos x plus b sin x into minus a sin x plus b cos x. This implies dy by dx equal to minus sin a cos x plus b sin x into v cos x minus a sin x. Hope you understood the solution and enjoyed the session, goodbye and take care.