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
12 years ago

Answer 1

@SithsAndGiggles would you be able to help me?

Answer 2

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

Answer 3

wow thats so much clearer...good!

Answer 4

x=1?

Answer 5

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
\[\cos\theta=1~~\text{and}~~\cos\theta=\frac{1}{2}\]

Answer 6

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