Question

If sin A + sin B = 2 then cos(A+B) =?

Answer 1

given  sin A + sin B = 2

this is only possible when value of sin theta is maximum = 1

∴ sina=1 and sinb=1

by using trigonometry table
a=90 and b=90

cos(90+90)
cos180
-1

hope it's help u