Question

Verify the Identity!
( tan^4 x - sec^4 k) = (1 - 2 sec^2 k)
Please help me! I'm sure this is a no brainer, but I have no clue how to solve this, I've tried many times and OS is my last resort, please explain how to solve this, anyone! :( please and thank you :O

Answer 1

try this:\[\Large \tan^2\alpha-1=\sec^2(\alpha) \]

Answer 2

\[\Large \tan^2x=\sec^2x-1 \]
Squaring both sides and that will do.

Answer 3

Sorry, should be a plus of course. Here again:\[\Large \tan^2x=\sec^2x+1 \]

Answer 4

\[
a^2-b^2=(a-b)(a+b)
\]

Answer 5

\[
\tan^2x+1 = \sec^2x
\]

Answer 6

yes you're right @wio, I messed this one up.

Answer 7

@Ikushinkan Still need help?

Answer 8

is this really an identity with two variables "x" and "k" ???

Answer 9

@spacelimbus

You get the identity wrong; it's: tan^2(x) + 1 = sec^2(x)