Question

А) sin 915°cos b– sin b sin 645°; б) sin (540° + b) sin (b + 810°); Помогите :)

Answer 1

Calculation A: sin 915°cos b – sin b sin 645°

To calculate the expression sin 915°cos b – sin b sin 645°, we need to evaluate the trigonometric functions and perform the necessary arithmetic operations.

Let's break down the calculation step by step:

1. Evaluate sin 915°: - We can use a calculator or a trigonometric table to find the value of sin 915°. - The value of sin 915° is approximately -0.866.

2. Evaluate cos b: - Since the value of b is not provided, we cannot determine the exact value of cos b. - We need more information to evaluate this part of the expression.

3. Evaluate sin b: - Similarly, since the value of b is not provided, we cannot determine the exact value of sin b. - We need more information to evaluate this part of the expression.

4. Evaluate sin 645°: - We can use a calculator or a trigonometric table to find the value of sin 645°. - The value of sin 645° is approximately 0.939.

5. Perform the arithmetic operations: - Substitute the values we have into the expression: -0.866 * cos b - sin b * 0.939. - Since we don't have the value of b, we cannot calculate the final result without additional information.

To provide a more accurate answer, please provide the value of b so that we can calculate the expression.