Multiplying trig functions

If(secx)(tanx) < 0, which of the following must be true?

I. tanx <0

II. scsx cotx < 0

III. x is in the third or fourth quadrant

So I first simplified secx * tanx into sinx/cos^2x using the property that tanx = sinx/cosx, and then i graphed it on my calculator, but I'm not sure what to do next.

Re: Multiplying trig functions

Quote:

Originally Posted by

**rasen58** If(secx)(tanx) < 0, which of the following must be true?

I. tanx <0

II. scsx cotx < 0

III. x is in the third or fourth quadrant

So I first simplified secx * tanx into sinx/cos^2x using the property that tanx = sinx/cosx, and then i graphed it on my calculator, but I'm not sure what to do next.

If $\displaystyle (\sec(x))(\tan(x)) < 0$ then one of the factors is negative and one is positive.

Think in terms of quadrants.

Re: Multiplying trig functions