4 cos 90 + 2 cos 180- ctg 90=? Cos 0 - cos 180 + sin 90 + tg 180

Question

4 cos 90 + 2 cos 180- ctg 90=?
Cos 0 - cos 180 + sin 90 + tg 180

Answer 1

4cos90+2cos180-ctg90=4*0+2*(-1)-0=-2
cos0-cos180+sin90+tg180=1-(-1)+1+0=3