Cos(2A)

**FJO** · September 16th 2008, 04:38 PM

Need help with these questions.

Let COSA=1/square root of 10

5.Cos2a

6.sin2a

7.cot2a

8.tan2a

**Jhevon** · September 16th 2008, 05:47 PM

Originally Posted by FJO

Need help with these questions.

Let COSA=1/square root of 10

5.Cos2a

6.sin2a

7.cot2a

8.tan2a

here are the identities you need

$\cos 2x = 2 \cos^2 x - 1$

$\sin^2 x + \cos^2 x = 1$

$\sin 2x = 2 \sin x \cos x$

$\cot 2x = \frac {\cos 2x}{\sin 2x}$

$\tan 2x = \frac {\sin 2x}{\cos 2x}$

Thread: Cos(2A)

LinkBack

Thread Tools

Display

Cos(2A)

Search Tags