2. Tan (A - B) = tan A - tan B)/(1+tan A.tan B)
= (3/4-15/8)/(1 + 3/4.15/8)
= ((6 - 15)/8)/(1 + 45/32)
=(-9/8)/(77/32)
= - 9/8 x 32/77 = -9(4)/77= -36/77
Jawab : D.
3. Tan(π/4 - A) = tan π/4 - tan A) / (1 + tan π/4.tan A) = 1 - tan A)/(1 + tan A)
Tan A = sin A/cos A
Berarti
(1-tan A)/(1 + tan A) = (1 - (sin A/cos A))/(1+(sin A/cos A)) = ((cos A - sin A)/(cos A))/((cos A + sin A)/(cos A))
= (cos A - sin A)/(sin A + cos A)
Jawab : A.
Nomor 6, saya kurang tau. Semoga membantu, maaf satu nomor tidak terjawab.