Question

how come sec inverse is equal to cos inverse

Answer 1

It isn't

Answer 2

then what is it equal to?

Answer 3

\[y=\sec^{-1}(x) => \sec(y)=x =>\frac{1}{\cos(y)}=x \]
\[=>\frac{1}{x}=\cos(y) => \cos^{-1}(\frac{1}{x})=y\]

Answer 4

\[=> \sec^{-1}(x)=\cos^{-1}(\frac{1}{x})\]

Answer 5

thanks