Question

Cos 65° cos 18° +sin 63° sin 18°​

Answer 1

Ответ:

Альтернативная форма : ≈0,67727

Объяснение:

cos65° cos18° + 1/2 cos45° - cos81° = cos65° cos18° + 1/2 * √2/2 * cos81° = cos65° cos18° + √2/4 - cos81°/2

Answer 2

The given expression is a combination of trigonometric functions. Let's break it down step by step:

1. Start with the expression: cos(65°) * cos(18°) + sin(63°) * sin(18°).

2. Use the trigonometric identity cos(A - B) = cos(A) * cos(B) + sin(A) * sin(B).

3. In this case, we can let A = 65° and B = 18°. Then the identity becomes: cos(65° - 18°) = cos(47°).

So, the simplified expression is: cos(47°).

Using a calculator, you can find the value of cos(47°), which is approximately 0.6820.