Question

show that cos38cos52-sin38sin52=0

Answer 1

Cos 38=sin(90-38)=sin 52 Cos 52= sin (90-52)=sin 38  Substitute this in main equation Sin38sin52-sin38sin52=0 Hence proved

Answer 2

$\huge{Hey Mate!!!}$

cos38° cos 52°− sin 38° sin 52°

= cos (90° − 52°)cos (90°−38°)− sin 38° sin 52°

= sin 52° sin 38°− sin 38° sin 52°

= 0

Hence proved!

HOPE IT HELPS.