10 ctg 3p/4 sin 5p/4 cos 7p/4

Question

10 ctg 3p/4 sin 5p/4 cos 7p/4

Answer 1

10ctg(p -p/4)sin(p+p/4)cos(2p-p/4)= -10ctgp/4( - sinp/4) cosp/4= 10cosp/4 / sinp/4 sin p/4 cos p/4= 10cos2 p/4 = 10 1/2=5