Question

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How do I verify the identity ?
1 - 2cos^2x = 2sin^2x - 1

Answer 1

Fraction it i would think.

Answer 2

Start with the left hand side and use the fact that cos^2 = 1 - sin^2

Answer 3

cos ² x - sin ² x
cos ² x - (1 - cos ² x)
cos ² x - 1 + cos ² x
2 cos ² x - 1

kinda like this?

Answer 4

sin x = cos (x-(pi/2))

Answer 5

I am not getting this.....

Answer 6

Pythagorean Identity and substitute it into the left hand side would help you solve this problem

Answer 7

oh okay... thanks :)

Answer 8

Np

Answer 9

Also try this http://math.tutorvista.com/trigonometry/trigonometric-identities.html

Answer 10

It should help you solve it.

Answer 11

how about this, this is an identity you should know \[\sin^2x+\cos^2x=1\] multiply both sides by 2\[2\sin^2x+2\cos^2x=2\] \[2\cos^2x=2-2\sin^2x\]\[2\cos^2x-1=1-2\sin^2x\]

Answer 12

I understand this now thanks and I will try out that website! Thanks for the help! @Blueskys @nathan917

Answer 13

no worries

Answer 14

@minnie123 Np anytime.

Answer 15

New similar problem up incase your not busy and wanna take a crack at it....