If n is an integer n 180 represents an integer multiple of 1

If n is an integer, n. 180° represents an integer multiple of 180° and (2n+ 1). 90° represents an odd integer multiple of 900, and so on. Determine whether the expression is equal to 0, 1 1, or is undefined cos((2n 1) 90°) cos((2n 1) 90°) 0 (Simplify your answer, including any radicals. Use integers or fractions for any numbers in the expression. Type N if the expression is undefined.)

Solution

cos((2n+1)*90) = cos( 180n +90)

use: cos(a+b) = cosacosb -sinasinb

=cos90cos(180n) - sin90sin(180n)

= 0 - 1*0

=0