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## Homework Statement

The two graphs are possible legitimate representations of ##y=\sec^{-1}(x)##.

The derivative is positive on all the domain and so is graph A, but graph B has negative tangent when x<-1

## Homework Equations

Derivative of inverse secant:

$$(\sec^{-1}(x))'=\frac{1}{x(\pm\sqrt{x^2-1})}$$

## The Attempt at a Solution

The derivative was established on all the domain, so i think it must be positive. the slope must be pointing upwards on all the domain.

I don't know.