Sin(x)= -2/(5^0.5), 3pi/2<x<2pi

then i have that cos(x)=+-(1-(-2/(5^0.5))^0.5=+-1/(5^0.5)

and tan(x)=((-2/(5^0.5))/(1/(5^0.5)=2

but what is the exaktly valus of this expression: cos(2x-3pi/4)?

Results 1 to 2 of 2

- Jan 10th 2011, 08:27 AM #1

- Joined
- Dec 2010
- Posts
- 52

## Value of cos(2x-3pi/4).

Sin(x)= -2/(5^0.5), 3pi/2<x<2pi

then i have that cos(x)=+-(1-(-2/(5^0.5))^0.5=+-1/(5^0.5)

and tan(x)=((-2/(5^0.5))/(1/(5^0.5)=2

but what is the exaktly valus of this expression: cos(2x-3pi/4)?

- Jan 10th 2011, 02:31 PM #2