Question

Cos 2t=cos^2 t-sin^2 t -cos 2t=?​

Answer 1

Ответ:

1

Пошаговое объяснение:

-соs 2t=cos^2t+sin^2t=1

Answer 2

To prove the trigonometric identity:

cos(2t) = cos^2(t) - sin^2(t) - cos(2t),

you can start with the right-hand side and manipulate it step by step:

cos^2(t) - sin^2(t) - cos(2t).

First, use the trigonometric identity for cos(2t):

cos(2t) = cos^2(t) - sin^2(t).

Now, substitute this expression back into the right-hand side of the original equation:

cos^2(t) - sin^2(t) - (cos^2(t) - sin^2(t)).

Now, distribute the negative sign inside the parentheses:

cos^2(t) - sin^2(t) - cos^2(t) + sin^2(t).

Now, you can see that the cos^2(t) and sin^2(t) terms cancel out:

cos^2(t) - cos^2(t) = 0.

So, the right-hand side simplifies to 0, which is equal to the left-hand side (cos(2t)). Therefore, the identity is proven:

cos(2t) = cos^2(t) - sin^2(t) - cos(2t).