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Mathematics 20 Online
OpenStudy (beautifulmymy123):

tan^2x + sec^2x = 1

OpenStudy (nerdsarecool):

What is the question

OpenStudy (beautifulmymy123):

Verify each trigonometric equation by substituting identities to match the right hand side of the equation to the left hand side of the equation.

OpenStudy (nerdsarecool):

Give me a sec

OpenStudy (nerdsarecool):

What kind of question is this

OpenStudy (lfreeman1285):

If you multiply everything by cos^2x then you'll have sin^2x + 1 = cos^2x, which is one of the other trig identities. I'm not sure if that helps or not.

OpenStudy (nerdsarecool):

You have so many people on it right now

OpenStudy (beautifulmymy123):

I dont get this problem at all. Why would I multiply it by cos ^2x?

OpenStudy (lfreeman1285):

Are you trying to relate all of the trig identities to eachother?

OpenStudy (beautifulmymy123):

yeah

OpenStudy (lfreeman1285):

The original one is sin^2x + cos^2x = 1. To get the other ones, you'd have to either divide by sin^2x or cos^2x. In the case of tan^2x - sec^2x = 1, sin^2x + cos^2x = 1 was divided by cos^2x. and then set equal to 1.

OpenStudy (anonymous):

\[\sec ^2x-\tan ^2x=1\] adding \[2 \sec ^2x=2\] \[\frac{ 2 }{ \cos ^2x }=2\] \[2 \cos ^2x=2,1+\cos 2 x=2,\cos 2x=2-1=1=\cos 2 n \pi\] \[2x= 2 n \pi,x=n \pi, \] where n is an integer.

OpenStudy (anonymous):

\[\tan ^2x+\sec ^2x=1\] it is not an identity. the problem can be solve it or find x.

OpenStudy (beautifulmymy123):

wait I might be wrong, so would it be sin^2x+cos^2x all divided by cos^2x?

OpenStudy (tkhunny):

No, you're not wrong. The sign doesn't match up.

OpenStudy (beautifulmymy123):

This is so confusing :/

OpenStudy (tkhunny):

Do it!! \(\sin^{2}(x) + \cos^{2}(x) = 1\) \(\dfrac{\sin^{2}(x)}{\cos^{2}(x)} + \dfrac{\cos^{2}(x)}{\cos^{2}(x)} = \dfrac{1}{\cos^{2}(x)}\) \(\tan^{2}(x) + 1 = \sec^{2}(x)\)

OpenStudy (lfreeman1285):

All of the trig functions are related by the unit circle (which has a radius of 1). the coordinates along the unit circle are similar to regular coordinates. The cosine value is equal to x. The sine value is equal to y. If you plug all those into the pythagorean theorem, then cos^2x + sin^2x = 1. From there, you either divide by sine or cosine to get the other trig identities. The original divided by sine is cot^2x + 1 = csc^2x The original divided by cosine is tan^2x +1 = sec^2x.

OpenStudy (beautifulmymy123):

ok i think i understand that

OpenStudy (lfreeman1285):

Therefore, I don't think the identity tan^2x + sec^2x = 1 can be verified.

OpenStudy (beautifulmymy123):

ok i think i understand that

OpenStudy (lfreeman1285):

Because its not one of the identities.

OpenStudy (tkhunny):

Really bad language. If it's an "Identity", it CAN be verified. If it cannot be verified, it is NOT an Identity.

OpenStudy (tkhunny):

It may be true for some values.

OpenStudy (beautifulmymy123):

Thank you. That is why I was so confused.

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