Question

simplify:
equation is in the answer box please help me

Answer 1

\[\frac{ 1 }{ \cos \theta }=\frac{ \sin2\theta \cos \theta- \cos2 \theta \sin \theta }{ \sin \theta \cos \theta }\]

Answer 2

hmmm, it just algebra ..

you either want to solve for theta, or show that this is an identity?

Answer 3

use the double angle identities to pull apart those 2thetas into sin cos parts that can be canceled or worked with better

Answer 4

It's a proof, amistre64.

Answer 5

thanks

Answer 6

can u solve it?

Answer 7

please help me

Answer 8

I can help you solve it. Do you have a sheet with all of the trig identities on it?

Answer 9

yes

Answer 10

And you understand that you have to change things on the more complicated side in order to reach the other side of this right?

Answer 11

yeah

Answer 12

Okay, so, double angles. What formulas do you have for those?

Answer 13

\[\sin 2 \theta = 2 \sin \theta \cos \theta\]

Answer 14

\[\cos 2 \theta = \cos ^{2} - \sin ^{2} = 1 - 2\sin^{2}\theta = 2\cos^{2} \theta -1\]

Answer 15

i have other ones but they dont really apply

Answer 16

So first I think you should change the sin2theta, on the left hand side, to the first formula you gave me

Answer 17

ok

Answer 18

I'm working on this :)

Answer 19

ok

Answer 20

Okay, this is all solved out. So what happens when you plug in that sin property?

Answer 21

Also, you're going to use the (cos^2theta-sin^2theta) for the cos2theta

Answer 22

Write that out and post it for me

Answer 23

i can only cancel out the cos (theta)

Answer 24

hello

Answer 25

You can cancel the sins