Question

If angle x=55% and angle y=35, calculate the following 1.cos(x+y) ​

Answer 1

cos(X+Y) = cos(55+35) = cos(90) = 0

Explanation:

cos(X+Y) = cosXcosY - sinXsinY

cos(55+35) = cos(55)cos(35) - sin(55)sin(35)

cos(55+35) = cos(55)cos(35) - cos(90-55)cos(90-35)

cos(55+35) = cos(55)cos(35) - cos(35)cos(55)

cos(55+35) = 0

cos(90) = 0