Prove the following identities

1.

2.

3.

Solve

1.

2.

These are the ones I couldn't solve from a worksheet I got in class. Please help

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- Dec 13th 2007, 03:34 PMHasan1Trig Identity Help (and solving)
Prove the following identities

1.

2.

3.

Solve

1.

2.

These are the ones I couldn't solve from a worksheet I got in class. Please help - Dec 13th 2007, 05:04 PMSoroban
Hello, Hasan1!

Here are the last two . . .

Quote:

*square*. . .

. .

Therefore: .

Quote:

We know the identity: .

Apply it to

We have: .

Multiply by

. .

Factor: .

The equation: . has no real roots.

So we have: .

- Dec 13th 2007, 05:51 PMHasan1
that second solving question has a nice solution, thanks!

I guess I never saw the perfect square trinomial in that first one though :D

thanks again :cool: - Dec 13th 2007, 06:31 PMKrizalid
- Dec 13th 2007, 07:15 PMKrizalid
- Dec 13th 2007, 07:22 PMKrizalid
- Dec 14th 2007, 07:56 PMHasan1
Is there a way to do those identities without the sum to product formula, but the double angle formula instead?

- Dec 15th 2007, 12:16 PMKrizalid
I think those identities were made to apply the formulae I gave you. It's a quickly way.