Question

Tan(A+45)-tan(A-45)=2(1+tan^2A)/1-tan^2A

Answer 1

Step-by-step explanation:

$\tan(a + 45) - \tan(a - 45) = \frac{ \tan(a) + 1 }{1 - \tan(a) } - \frac{ \tan(a) - 1}{1 + \tan(a) } \\ \\ = \frac{ { \tan(a) }^{2} + 1 + 2 \tan(a) - (1 + { { \tan(a) }^{2} - 2 \tan(a)) }^{} }{1 - { \tan(a) }^{2} } \\ \\ = 2( \frac{1 + { \tan(a) }^{2} }{1 - { \tan(a) }^{2} } ) = rhs.$

L.H.S = R.H.S.