Friday

October 31, 2014

October 31, 2014

Posted by **Marie** on Wednesday, May 23, 2007 at 10:36pm.

"...other angle identity of tan x"?

in relation to which "other" ?

there are many identities dealing with the tangent.

The most important is probably

tan x = sin x/cos x

The Pythagorean Relationship would be

tan^2 x + 1 = sec^2 x

how about tan(2A) = 2tan A/(1-tan^2 A)

yes, i do know those, thank you. but my teacher told us that there is a specific identity for "the other angle". for example, the other angle identity of sinx = cos90-x. I believe the "other angle" identity for tanx is cot90-x but i'm not sure.

yes, you are right, tanx = cot(90-x)

if you are ever unsure about an identity like that pick an obscure angle such as 78.4º and test it with your calculator

tan 78.4 = 4.87162

cot(90-78.4)=cot 11.6º = 1/tan 11.6 = 4.87162

**Answer this Question**

**Related Questions**

math - could someone please tell me what the other angle identity is? Thank you ...

Pre-Calc (Prove the identity) - Prove the identity. (show your work please) tan(...

Pre-Cal - 1)tan 5 degrees + tan 25 degrees / 1 tan 5 degrees tan 25 degrees = ...

Trigonometry - Find the exact value of tan(a-b) sin a = 4/5, -3pi/2<a<-pi...

pre-cal - find all solutions in interval [0,2pi] tan²x = -3/2 secx This question...

precalc pre ap - If theta is a rotation angle that terminates in quadrant ll and...

Pre-Calc Help!!! - Prove the identity. (show your work please) tan(x − &#...

Pre-Cal - Perform the addition or subtraction. tanx - sec^2x/tanx tan^2(x)/tan(x...

pre cal - verify each identity tan(x/2)=tanx/secx+1

trig - h t t p : / / i m g 4 0 . i m a g e s h a c k . u s / c o n t e n t . p h...