Question

tan(45+a)-tan(45-a)=

Answer 1

\[(1+tanA)/(1-tanA) + (1-tanA)/(1+tanA)=
=\[((1+tanA)^2-(1-tanA)^2)/1-\tan^2\]
=\[4tanA/1-\tan^2A\]

Answer 2

1) 2cot2a 2)2sin2a 3) 2tan2a 4)cot^2(a)- 5 These are the only choices I have. Thank you for your response.