I'm not sure if i'm doing this problem correctly. :

cot z sin z + tan z cos z

Heres one way i did it:

cotz = (cos / sin) sin z

= cos z

= cot z + (sin/cos) cos z

This is what i'm left with:

= cot z + cos z

Printable View

- Mar 22nd 2011, 05:52 AMMajorJohnsonNeed help on using trig functions to verify identities
I'm not sure if i'm doing this problem correctly. :

cot z sin z + tan z cos z

__Heres one way i did it:__

cotz = (cos / sin) sin z

= cos z

= cot z + (sin/cos) cos z

This is what i'm left with:

= cot z + cos z - Mar 22nd 2011, 05:58 AMmasters
- Mar 22nd 2011, 07:39 AMMajorJohnson

Quote:

Hi MajorJohnson,

I don't see an identity here, but if you just want to simplify....

And the method you did, was the other way i had tried to solve it and got the same answer. I just wasn't sure if it was right or not.

Thanks.

Code:`Here's another one i'm stuck on:`

1 - sin^2 / csc^2 - 1 =

Heres what i've gottten so far:

1/csc ^ 2 - sin ^ 2 / 1 =

Here's another one

sec x * sin x/tan x =

1 / cos x * sin x / sin x /cos x

(sin x / cos x ) (sin x / cos x) =

sin x /cos x ^ 2 * sin x =

answer:

sinx ^ 2 / cos x ^ 2 - Mar 22nd 2011, 07:50 AMe^(i*pi)
- Mar 22nd 2011, 08:50 AMmasters
- Mar 22nd 2011, 01:29 PMMajorJohnson
okay, thank you. One more question, how do you get your equations to look like that in your post?

- Mar 22nd 2011, 03:00 PMskeeter
- Mar 24th 2011, 12:52 PMMajorJohnson
Thanks,

I might just keep using this thread to post more problems, up just to make sure i understand this. After working through these for some time, i feel like i'm almost comfortable with proving trig identities.

1)

2)

For this problem, does it matter if the right side's answer is the same value on the left side but flipped?

3)

Doing the right side:

- Mar 24th 2011, 01:50 PMskeeter