If `f(x)=sinx+cosa x` is a periodic function, show that `a` is a rational number

If f(x)=sin x+cos ax is a periodic function,show that a is a rational number

If f(x) = sinx + cos ax is a periodic function then a cannot be

If f(x)=cosx+cosa x is periodic function, then a must be (a)an integer (b) a rational number (c)an irrational number (d) an even number

If f(x)=cos x+cos ax is periodic function, then a must be (a)an integer (b) a rational number (c)an irrational number (d) an even number

If f(x) is periodic function of period t show that int_(a)^(a+t)f(x)dx is independent of a.

If f(x + 2a) =f(x - 2a), then f(x) is a)a periodic function with period 4a b)a periodic function with period 2a c)a periodic function with indeterminate period d)a non periodic function

The function f(x)=x-[x] is a periodic with period.