Medals for you! can i have some help from the people at open study?
solve each equation
1.2cos^2(theta)-3cos(theta) +1=0 , 0

Question

Medals for you! can i have some help from the people at open study? solve each equation 1.2cos^2(theta)-3cos(theta) +1=0 , 0

anonymous · Answer

@SithsAndGiggles would you be able to help me?

anonymous · Answer

It's a quadratic in disguise. Try writing $x=\cos\theta$ to make it easier to see:
$$2x^2-3x+1=0$$

anonymous · Answer

wow thats so much clearer...good!

anonymous · Answer

x=1?

anonymous · Answer

Not quite, you can factor the expression:
$$2x^2-3x+1=(2x-1)(x-1)=0$$
which gives $x=1$ *and* $x=\dfrac{1}{2}$.

Remember that $x=\cos\theta$, so in fact you have
$$\cos\theta=1~~\text{and}~~\cos\theta=\frac{1}{2}$$

anonymous · Answer

right, which makes a lot more sense..this is great, honestly thanks for helping me with such a simple one! thanks XD