[aussie_kris]

Hey

how do I solve

2cos^2($) + sin ($) = 1

Any help would be great

[aussie_kris]

Hey I need to solve it for theta -pie to pie

[aussie_kris]

Hey thanks

I think that's what I need

also any hints with expressing cos3($) in terms of sin and sin3($) in terms of cos??

[aussie_kris]

How did u get 5.176?? I got -63.435

[shanus]

Ahhhh... I hate to burst eveyone's bubble here, but...

Cos2($) is not equal to 2x/r

i.e.. Cos2($) is not equal to 2Cos($)

I think a lot of Mathematicians would be upset if this were true ;)

[MathMaven53]

Let's express the equation in terms of Sin(x)

We have 2 Cos^2 (x) + Sin(x) =1

We use Cos^2 (x) = 1 - Sin^2(x)

After substituting and simplifying we get the equation

2 Sin^2(x) - Sin(x) - 1 = 0

Factor this into

(2Sin(x) + 1)(Sin(x) -1) = 0

Now set each factor equal to zero,solve for Sin(x) and then x