Question

Which of the following is an identity?

A. sinx - cosx + 1 = tanx
B. (1 - 2sin2x)csc2x = 4cos2x - 2
C. tan2x + cot2x = 1
D. sin2x cot2x + cos2x tan2x = 1

Answer 1

A looks like it has stuff added to it.
\[\large \sin^2(x)+\cos^2(x) = 1\]

Answer 2

what do you mean?

Answer 3

We know the identity s^2 +c^2 = 1. But whats tan(x) doing there?

Answer 4

idk :c lol

Answer 5

it shouldn't be there

Answer 6

so the answer is A ?

Answer 7

Nope, i'm just going down the list one by one :D

Answer 8

lol c: i think its B though like my gut is leaning towards it :D

Answer 9

Lets go with B now. \[\large (1-2\sin^2(x))(\csc^2(x))\]\[\large \csc^2(x) - 2\sin^2(x)\csc^2(x)\]hmmm...

Answer 10

idk it could be C

Answer 11

it's actually D


sin^2x cot^2x + cos^2x tan^2x = 1


sin^2x (cos^2x/sin^2x) + cos^2x (sin^2x/cos^2x) = 1


cos^2x + sin^2x = 1


1 = 1

Answer 12

@jim_thompson5910 thank you !!! :)

Answer 13

np

Answer 14

I'm still relearning trig too. haha.