Question

cos5A cos6A+sin5A sin6A

Answer 1

Answer:

Step-by-step explanation:

       its of the form of the formula cos(m-n)

                       using above gives u cos(6A-5A) = cosA

                   and formula is cos m cosn + sinm sin n = cos(m-n)

           remember this formula

                   hopr u get it mate.................

Answer 2

Answer:

here, formula is used, formula is[ cos (A - B) ]