Trig Problem Help

[sherbs]

Hi guys! My name is Shelby. I was hoping to get an explanation for a problem that I'm having trouble on if anyone doesn't mind helping me.
So, the instructions say to "use identities to simplify each expression." I'm really having trouble on this one problem.
sin²x-cos²x/1-2cos²x

I've looked in the back of the book, and the answer is 1. I just don't know how to get it.
Thanks!

 

[srmichael]

Hi guys! My name is Shelby. I was hoping to get an explanation for a problem that I'm having trouble on if anyone doesn't mind helping me.
So, the instructions say to "use identities to simplify each expression." I'm really having trouble on this one problem.
sin²x-cos²x/1-2cos²x

I've looked in the back of the book, and the answer is 1. I just don't know how to get it.
Thanks!

Use the fact that sin²x + cos²x = 1. Thus, sin²x = 1 - cos²x.

I'll let you finish.

 

[Deleted member 4993]

Hi guys! My name is Shelby. I was hoping to get an explanation for a problem that I'm having trouble on if anyone doesn't mind helping me.
So, the instructions say to "use identities to simplify each expression." I'm really having trouble on this one problem.
sin²x-cos²x/1-2cos²x

I've looked in the back of the book, and the answer is 1. I just don't know how to get it.
Thanks!

Please use grouping symbols to post the problem correctly.

What you posted → sin²x-cos²x/1-2cos²x → sin²x - cos²x - 2cos²x → sin²x - 3cos²x

What I think you should have posted → (sin²x-cos²x) / (1-2cos²x) ← Watch those parentheses () - those are very important.

Now follow SirMichael's suggestions.....

 

[sherbs]

Use the fact that sin²x + cos²x = 1. Thus, sin²x = 1 - cos²x.

I'll let you finish.

Thanks for the help! I really appreciate it! Sorry about the formatting of my problem, though!