Question

Sin 30°×cos 60°-cos 30°​

Answer 1

1/4 + 3/4 складываем числители

1+3/4

4/4

4:4=1

Answer 2

To evaluate the expression sin(30°) × cos(60°) - cos(30°), you can use trigonometric identities and values. Let's break down each part step by step:

1. sin(30°): The sine of 30 degrees is 0.5. This is a common value in trigonometry.

2. cos(60°): The cosine of 60 degrees is 0.5. This is also a well-known trigonometric value.

3. cos(30°): The cosine of 30 degrees is (√3) / 2.

Now, plug these values into the expression:

sin(30°) × cos(60°) - cos(30°) = (0.5) × (0.5) - (√3) / 2 = 0.25 - (√3) / 2

To make the expression more readable, you can express the first term with a common denominator:

= (0.25 * 2) / 2 - (√3) / 2 = 0.5 / 2 - (√3) / 2 = (0.5 - √3) / 2

So, sin(30°) × cos(60°) - cos(30°) simplifies to (0.5 - √3) / 2.