Question

use a calculator to find the value of sec-1(6.2)
how do i enter this in my ti83

Answer 1

you are trying to solve
\[\frac{1}{\cos(x)}=6.2\] for x so
\[\cos(x)=\frac{1}{6.2}\] and therefore
\[x=\cos^{-1}(\frac{1}{6.2})\]

Answer 2

\[\cos(\theta)=\frac{adj}{hyp} ; \sec(\theta)=\frac{hyp}{adj}\]
remember \[\frac{1}{\cos(\theta)}=\sec(\theta)\]
\[\theta=\sec^{-1}(\frac{1}{\cos(\theta)})=\sec^{-1}(\frac{hyp}{adj})\]
\[\cos(\theta)=\frac{1}{\sec(\theta)}\]
\[\theta=\cos^{-1}(\frac{1}{\sec(\theta)})=\cos^{-1}(\frac{adj}{hyp})\]
=>
\[\cos^{-1}(\frac{adj}{hyp})=\sec^{-1}(\frac{hyp}{adj})\]