What is the answer of the Cos(n+1)a.cos(n-1)+sin(n+1)a.sin(n-1)a=

Is it possible to attend the class 9 online test session only? Based on the class room practice, need to attend the online test sessions.

What is the answer of  cos(n+1)a.cos(n-1)a+sin(n+1)a.(n-1)a=

Find the coordinates of a point on the x-axis which is equidistant from

(1, 2) and (5, 6).

Factorize the expression      X⁴+324.   Idk how to solve it