If x1(t) = 2 sin πt + cos 4 πt and x2(t) = sin 5 πt + 3 sin 13 πt , then

x1 is not periodic ; but x2 is periodic

If x1(t) = 2 sin πt + cos 4 πt and x2(t) = sin 5 πt + 3 sin 13 πt

1.	If x1(t) = 2 sin πt + cos 4 πt and x2(t) = sin 5 πt + 3 sin 13 πt , then
A.	x1, x2 both periodic
B.	x1 x2 both not periodic
C.	x1 periodic, x2 not periodic
D.	x1 is not periodic ; but x2 is periodic
Answer» B. x1 x2 both not periodic