# Determine tanx if secx=(sqrt14)/2 and is in the second quadrant

• Apr 6th 2009, 07:22 AM
skeske1234
Determine tanx if secx=(sqrt14)/2 and is in the second quadrant
Can someone explain this to me please?

Determine tanx if secx=(sqrt14)/2 and is in the second quadrant

How would I approach this because I am confused about the sqrt14 and when I did get tan, it was -0.098etc. or something with that.. if it's negative and decimals, can tanx be correct?
• Apr 6th 2009, 08:08 PM
pickslides
Quote:

Originally Posted by skeske1234
Can someone explain this to me please?

Determine tanx if secx=(sqrt14)/2 and is in the second quadrant

How would I approach this because I am confused about the sqrt14 and when I did get tan, it was -0.098etc. or something with that.. if it's negative and decimals, can tanx be correct?

I would say if sec(x) = sqrt(14)/2 then cos(x) = 2/sqrt(14)

The Six Trigonometric Functions

From here you can use sin^2(x)+cos^2(x) = 1

Subbing in for cos(x) and solving for sin(x) you will get

sin(x) = sqrt(8)/sqrt(14)

Now use tan(x) = sin(x)/cos(x)

This should give tan(x) = sqrt(2), thisanswer is in the 1st quadrant.

tan is negative in the 2nd quadrant so tan(x) = -sqrt(2)