Question

If 2cos∅ = √3, find the value of 2cos∅+1/2cos∅-1.

Answer 1

$2\cos\Theta=\sqrt3\to\cos\Theta=\dfrac{\sqrt3}{2}\\\\2\cos\Theta+\dfrac{1}{2}\cos\Theta-1=\sqrt3+\dfrac{1}{2}\cdot\dfrac{\sqrt3}{2}-1=\dfrac{4\sqrt3}{4}+\dfrac{\sqrt3}{4}-\dfrac{4}{4}\\\\=\boxed{\dfrac{5\sqrt3-4}{4}}$