Question

what is the value of cos(2npi)??

Answer 1

cos(0) = 1
When you make 1 full 2pi rotation, you end up at the same place.
So cos(2*n*pi) = cos(0) = 1.

Answer 2

cos(npi)=??

Answer 3

Depends on the value of n.
If n is even, cos(n*pi) = cos(0) = 1
If n is odd, cos(n*pi) = cos(pi) = -1

Answer 4

sin(npi)=??
sin(2npi)=??

Answer 5

sin(npi). Put n = 0, 1, 2, 3, .... sin(0) = 0, sin(pi) = 0, sin(2pi) = 0, sin(3pi) = 0.
So sin(npi) = 0 for all integer values of n.
sin(2npi). Put n = 0, 1, 2, .... sin(0) = 0, sin(2pi) = 0, sin(4pi) = 0
So sin(2npi) = 0 for all integer values of n.

Answer 6

thanks a lot....

Answer 7

you are welcome.