1. Jan 23, 2006

### kevinlikesphysics

i had a test and i got a 55 can someone show me how to do these with the steps if possible

verify each of the folloring trigonomic identities

1) 2sin^2x - 1/sinx-cosx = sinx+cosx*

did my steps wrong

2) cot^2x-cos^2x = cos^2xcot^2x

didnt get an answer <no clue how to do

simplify

1) 1+tanx/sinx+cosx*

1+ sec^2x <dont know

2) (sinx - 1)(tanx+secx)

i got cot^2x+1 < dont know

can someone just explain how to do them and work at least one or two out for me so i can pass the quiz thanks alot the one swith the stars " * " are the ones i got the most points of any anyone who would work one of them out for me would be awsome

Last edited: Jan 23, 2006
2. Jan 23, 2006

### StatusX

For the first one, you must mean:

(2sin^2x - 1)/(sinx-cosx)

Try to be clearer with your notation. And what exactly is it that you say is wrong on the next line? Anyway, just expand one of the sin^2's in the numerator into 1-cos^2 and you'll get the difference of two squares, at which point you can factor and cancel.

3. Jan 23, 2006

### kevinlikesphysics

no it suposed to equal that you are suposed to verify that they are equal

4. Jan 23, 2006

### Math Is Hard

Staff Emeritus