Question

-tan^2x+sec^2x=1

Answer 1

Verify by using identities

Answer 2

was just about to fly through, but,

can I work 2 sides at once, or I have to work one side the entire time (independently) ?

Answer 3

working one side independently,
\[-\tan^2x+\sec^2x=1\]
\[\color{red} { - \frac{\sin^2x}{\cos^2x} + \frac{1}{\cos^2x} } \]
\[\color{red} { \frac{-\sin^2x+1}{\cos^2x} } \]
\[\color{red} { \frac{1-\sin^2x}{\cos^2x} } \]
\[\color{red} { \frac{\cos^2x}{\cos^2x} } \]
\[\color{red} { 1 } \]

I worked the left side in red. VERIFIED.