proving identities

[anne baracena]

Prove that (1/1-csc A) + (1/ 1+csc A) is equal to -2csc square A

 

[Ishuda]

I believe something is wrong here and the statement is not true except for particular angles.

 

[Quaid]

Prove that (1/1-csc A) + (1/ 1+csc A) is equal to -2csc square A

The equation above is not an identity, but this one is:

1/(1 - csc[A]) + 1/(1 + csc[A]) = -2/(csc[A]^2 - 1)

 

[Deleted member 4993]

The equation above is not an identity, but this one is:

1/(1 - csc[A]) + 1/(1 + csc[A]) = -2/(csc[A]^2 - 1)

So the original problem could have been:

Prove that 1/(1-csc A) + 1/ (1+csc A) is equal to -2tan square A

 

[Quaid]

So the original problem could have been [written with 2*tan(A)^2]

Yes, of course. I wish I had seen (posted) that!