Question

show that tan3A.tan2A.tanA=tan3A-tan2A-tanA

Answer 1

here is your answer above the attachment hope its helpful

Answer 2

tan(3A-2A)=tan3A-tan2A/1+tan3A.tan2A

tanA=tan3A-tan2A/1+tan3A.tan2A

tanA+tanA.tan2A.tan3A=tan3A-tan2A

tanA.tan2A.tan3A=tan3A-tan2A-tanA....