Question

which of the following is an identity?
A) sin^2x sec^2x+1=cot^2x csc^2x
B) sin^2x-cos^2x=1
C) (cscx+cot)^2=1
D) csc^2x+cot^2x=1

Answer 1

i think its b)

Answer 2

it's not b)

the identity should be \(\sin^2 x + \cos^2 x = 1\)

Answer 3

b is not correct. sin^2x + cos^2x = 1

Answer 4

I wrote B correctly..that is why I'm confused

Answer 5

another identity you should know \(1 + \cot^2 x = \csc^2 x\)

Answer 6

therefore \(\csc^2 x - \cot^2 x = 1\)

Answer 7

are you following my logic @mInnocenti ? do you get what im implying?

Answer 8

I'm following. thank you :)

Answer 9

so do you know the correct answer now?

Answer 10

b)

Answer 11

Hold on, option C is not the same as \[\csc^2x−\cot^2x=1\]
\[C= \csc^2x + 2 cotxcscx + \cot^2x\]

Answer 12

who said it was c? lol

Answer 13

Oh I hadn't seen that option....lol never mind.

Answer 14

I thik it's b? lol

Answer 15

b is not correct as stated earlier.

Answer 16

Look at what @lgbasallote told you. B is incorrect.

Answer 17

D

Answer 18

lgbasallote also told you that csc^2x - cot^2x =1 which implies csc^2x + cot^2x cannot equal 1 as well...

Answer 19

right...I think I'm too weary to be of help right now, lol
But remember also \[\sec^2x-1=\tan^2x\]

Answer 20

only A is left.. lol

Answer 21

Thank you everyone!

Answer 22

exactly lol