Question

tan^2∅ - 1/cos^2=-1
please anyone can tell the answer
100 pts

Answer 1

Answer:

${ \tan( \alpha ) }^{2} - \frac{1}{ { \cos( \alpha ) }^{2} } \\ = \frac{ { \sin( \alpha ) }^{2} }{ { \cos( \alpha ) }^{2} } - \frac{1 }{ { \cos( \alpha ) }^{2} } \\ = \frac{{ \sin( \alpha ) }^{2} - 1}{ { \cos( \alpha ) }^{2} } \\ \\ = \frac{ { \cos( \alpha ) }^{2} }{ { \cos( \alpha ) }^{2} } \\ = 1$