Question

Cos^22a-sin^22a=алгебра 9кл ​

Answer 1

Ответ:

это даёт нам cos2(2a)(косинус двойного угла)=соs(4a)

Answer 2

To simplify the expression cos^2(a) - sin^2(a), we can use the trigonometric identity:

cos^2(a) - sin^2(a) = cos(2a)

This identity is known as the double angle identity for cosine. It states that the difference of squares of sine and cosine functions is equal to the cosine of twice the angle.

Therefore, cos^2(a) - sin^2(a) simplifies to cos(2a).

Please note that you mentioned "алгебра 9кл" which translates to "algebra 9th grade." It's great to see that you're studying algebra! Trigonometric identities like this one are commonly covered in algebra courses, and they help simplify expressions involving trigonometric functions.