Question

Cos(3x)cos(x)-sin(3x)sin(x)

Answer 1

Ответ:

cos(4x)

Объяснение:

По формуле косинуса суммы ответ: cos(4x)

Answer 2

The expression you provided can be simplified using trigonometric identities. In this case, you can use the trigonometric identity for the cosine of the difference of two angles, which states:

cos(A - B) = cos(A)cos(B) + sin(A)sin(B)

In your expression, A = 3x and B = x. Therefore:

cos(3x)cos(x) - sin(3x)sin(x) = cos(3x - x)

Now, simplify the angle:

3x - x = 2x

So, the simplified expression is:

cos(2x)