Wednesday

April 16, 2014

April 16, 2014

Posted by **Joe** on Wednesday, July 13, 2011 at 4:03pm.

I'm not sure how to properly square the -1/sqrt10 and keep an exact answer other than decimal. Otherwise, my final answer is 1.632455533

- Pre-Calculus -
**bobpursley**, Wednesday, July 13, 2011 at 5:24pmif sintheta=-1/sqrt10, then

costheta= (10-1)/sqrt10= sqrt (9/10)

check those.

Then sin2theta= sintheta*costheta=-2/sqrt10*sqrt9/10

= sqrt9 /5=3/5=.6

cos2Theta=1-2sin^2 theta=1-2(1/10)=.8

check all that. I have no idea what you did.

**Related Questions**

trig - Given that SIN Theta = -1/sqrt(10) and theta is in quadrant 4, find ...

easy trig - If sin(theta)=[sqrt(70)]/7 and theta is in Quadrant two, find the ...

simple trig - If sin(theta)=[sqrt(70)]/7 and theta is in Quadrant two, find the ...

math - theta is a first quadrant angle in standard position and cos theta = 1/(...

Math - 1. Let (-7, 4) be a point on the terminal side of (theta). Find the exact...

Precalculus check answers help! - 1.) Find an expression equivalent to sec theta...

Precalculus check answers help! - 1.) Find an expression equivalent to sec theta...

Trig - Find the exact value of sin2(theta) if cos(theta) = -sqrt 5/3 and 180 <...

math - tan theta= 15/8 and pi< theta<3pi/2 a. Sin(- theta) b. cos2theta c...

Trig - Let (theta) be an angle in quadrant II such that sec(theta) -4/3 . Find ...