mohon bantuannya mas soalnya dikumpulkan besok

tan 65° = tan (90 - 25)° = cotan 25°
cos 65° = cos (90 - 25)° = sin 25°
tan 25°.tan 65° - sin25°/cos65°
=tan 25°. cotan 25°- sin25°/sin25°
= tan 25°. 1/tan25°-1
=1 - 1
= 0