SOLUTION: prove this identity: tan to the second power theta + sec to the second power theta = 2 sec to the second power theta - 1

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Question 34343: prove this identity: tan to the second power theta + sec to the second power theta = 2 sec to the second power theta - 1
Answer by longjonsilver(2297) About Me  (Show Source):
You can put this solution on YOUR website!
Prove that
+tan%5E2%28A%29+%2B+sec%5E2%28A%29+=+2sec%5E2%28A%29+-+1+

This is a straightforward one to prove, since we know that +tan%5E2%28A%29+%2B+1+=+sec%5E2%28A%29+.

Using, this as +tan%5E2%28A%29+=+sec%5E2%28A%29+-+1+ we can sub this into the right hand side as:

+tan%5E2%28A%29+%2B+sec%5E2%28A%29+
+sec%5E2%28A%29+-+1+%2B+sec%5E2%28A%29+
--> +2sec%5E2%28A%29+-+1+

jon.