Question

2 cos2 30°-1=1-2sin2 30°=cos60°

Answer 1

Step-by-step explanation:

$2\cos^2 30-1\\=2\cos^2 30-\cos^230-\sin^230\\=\cos^230-\sin^230\\=\cos^2 30 +\sin^2 30-2\sin^2 30\\=1-2\sin^230\\=1-2(1/2)^2\\=1-1/2\\=1/2\\=\cos 60$

Hence Proved.

<Hope this helps m8>