Question

4sin450* + 3cos120* +7sin390* = ?

Answer 1

4sin(450*) + 3cos(120*) + 7sin390*) = 4sin(360* + 90*) + 3cos(180* - 60*) + + 7sin(360* + 30*) = 4sin90* - 3cos60* + sin30* = 4*1 - 3*(1/2) + 1/2 = 3