I can not factor
4 x^2 + 2x -1
i need to factorise 4 cos squared theta + 2 cos theta - 1
2 answers
Let's let cos theta = x.
You want to factor
4x^2 + 2x -1
Use the standard quadratic equation.
The roots are
x = (1/8)[-2 +/-sqrt20]
= (1/4)[-1 +/-sqrt5]
The factors are
(x - (1/4)(1 - sqrt5)][x - (1/4)(1 + sqrt5)]
Substitute back costheta for x if you with.
Check my work for algebra mistakes.
You want to factor
4x^2 + 2x -1
Use the standard quadratic equation.
The roots are
x = (1/8)[-2 +/-sqrt20]
= (1/4)[-1 +/-sqrt5]
The factors are
(x - (1/4)(1 - sqrt5)][x - (1/4)(1 + sqrt5)]
Substitute back costheta for x if you with.
Check my work for algebra mistakes.
2 answers