Question

If tan(a+b)=7 and tan(a-b)=5 find the value of tan 2b

Answer 1

Explanation:

Hi ,

tan ( A+ B ) = 3 ----( 1 )

tan (A - B ) = 5 ----( 2 )

tan 2A

= tan[ (A+ B ) + ( A - B ) ]

= [ tan(A+B)+tan(A-B)]/[1-tan(A+B)tan(A-B)]

= ( 3 + 5 ) / [ 1 - ( 3 × 5 ) ] from ( 1 ) & ( 2 )

= 8 / ( 1 - 15 )

= 8 / ( - 14 )

= - 4 / 7

I hope this helps you.

:)