Question

Cos5a напишите фрормулу

Answer 1

Нужно использовать формулу суммы косинусов:
2cos(5a+7a)/2*cos(5a-7a)/2=2cos6a*cos(-a)=2cos6a*cosa.

Answer 2

Formula for Cosine of 5a

The formula for the cosine of 5a can be expressed using the multiple angle formula for cosine. The multiple angle formula for cosine states that:

cos(5a) = 16cos^5(a) - 20cos^3(a) + 5cos(a)

This formula allows us to calculate the cosine of 5a in terms of the cosine of a.