Question

Cos square 30 degree minus sin square 30 degree is equals to 1 minus 2 sin square 30 degree​

Answer 1

see explanation

Explanation:

Not sure quite what you are asking, but

Using the trigonometric identity

cos² x = 1 - sin²x, then

cos²x - sin²x

= 1 - sin²x - sin²x

= 1 - 2sin²x

Thus

cos²30° - sin²30° = 1 - 2sin²30°