Question

$plzz \: help \: me \: in \: this....$

(b) 2 cos^2 30° - 1 = 1 - 2 sin^2 30º = cos 60°​

Answer 1

I hope this help helps you and kisiko aise mat bolo ha question ko pehle samajna parta hain samjhi

Answer 2

The answer is  $\frac{1}{2}$

Step-by-step explanation:

Given that

2 cos^2 30° - 1 = 1 - 2 sin^2 30º = cos 60°​

∴ cos 30° = $\frac{\sqrt{3}}{2}$ , sin 30° = $\frac{1}{2}$ , and cos 60° = $\frac{1}{2}$

∵ cos² 30° =$\frac{3}{4}$ and sin² 30° = $\frac{1}{4}$

The above equation is solve into three steps that can be described as follows:

Step 1:

2 cos^2 30° - 1

= 2 ×$\frac{3}{4}$  -1

= $\frac{3}{2}$ -1

=$\frac{3-2}{2}$

=$\frac{1}{2}$

Step 2:

1 - 2 sin^2 30°

= 1- 2×$\frac{1}{4}$

=1- $\frac{1}{2}$

=$\frac{2-1}{2}$

=$\frac{1}{2}$

Step 3:

cos 60° = $\frac{1}{2}$

by solving all step it will get $\frac{1}{2}$ ,that why answer is $\frac{1}{2}$

Learn more:

• Sin 30: https://brainly.com/question/6326779
• Cos 30: https://brainly.com/question/4398061