# Trigonometry Equation

by Dragonetti
Tags: maths, trigonometry
 P: 15 1. The problem statement, all variables and given/known data Hi, This isn't a homework question, I am having a bit of trouble with some Trig equations. If you are worried that you are answering a homework question please give me the solution to a similar question. 2. Relevant equations When we have a trig equation like sec2X + tan2X = 6. I know that sec is equal to 1/cos, and tan is equal to sin/cos, but what do I do with the square? Do I square all the terms or just the denominator? 3. The attempt at a solution I have tried many times, to many to list here! Thanks for your help Dominic
 PF Gold P: 1,160 Hint: is there a Pythagorean identity that relates secant and tangent?
HW Helper
Thanks
P: 26,148
Hi Dominic!
 Quote by Dragonetti When we have a trig equation like sec2X + tan2X = 6. I know that sec is equal to 1/cos, and tan is equal to sin/cos, but what do I do with the square? Do I square all the terms or just the denominator?
The whole thing …

tan2x = sin2x/cos2x
(and you can also use one of the standard trigonometric identities

sec2x = tan2x + 1, same as 1/cos2x = sin2x/cos2x + cos2x/cos2x )

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