Question

tan ( 45ᵒ + A ) tan ( 45ᵒ - A ) = ​

Answer 1

Answer:

$\tan( {45}^{0} + a) \tan( {45}^{0} - a ) \\ = \frac{ \tan {45}^{0} + tana }{1 - tan \: a. \tan {45}^{0} } . \frac{ \tan {45} ^{0} - tana }{1 + tan \: a. \tan {45}^{0} } \\ = \frac{1 + \tan a}{1 - tana} . \frac{1 - tana }{1 + tana} \\ = \frac{1 - { \tan }^{2}a }{1 - { \tan }^{2}a } \\ = 1$