Hi,

I tried to express tan(5 ) in terms of tan( ) but ican't do it, can you help me please??

Thanks.

Results 1 to 3 of 3

- October 4th 2010, 03:25 PM #1

- Joined
- Aug 2009
- Posts
- 62

- October 4th 2010, 05:20 PM #2

- October 4th 2010, 06:39 PM #3

- Joined
- May 2006
- From
- Lexington, MA (USA)
- Posts
- 11,715
- Thanks
- 633

Hello, lehder!

If we are allowed to use DeMoivre's Theorem,

. . there is a clever solution.

We are told that: .

Expand the right side:

. .

. . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

Equate real and imaginary components:

. .

We have: .

. . . . . . . . . . . . .

Divide numerator and denominator by

. .

. .