Question

2 tan A tan B = 1 find cos(A-B)/cos(A+B)

Answer 1

Answer:

Given that 2tanA. tanB=1 or tanA.tanB=1/2

Now cos(A-B) / cos(A+B)

= (cosA.cosB+sinA.sinB) / (cosA.cosB-sinA.sinB)

Divide cosA. cosB

=(1+tanA.tanB) / (1-tanA.tanB)

=(1+(1/2) ) / (1-(1/2) )

=3

Answer 2

Answer:

Given

2tanA. tanB=1

tanA.tanB=1/2        

cos(A-B) / cos(A+B)

= (cosA.cosB+sinA.sinB) / (cosA.cosB-sinA.sinB)     Divide by cosA. cosB

=(1+tanA.tanB) / (1-tanA.tanB)

=(1+(1/2) ) / (1-(1/2) )

=3

Step-by-step explanation: