Question

1)cos²45°-tg²60°2)2cos²60-sin²30 +sin60ctg60​

Answer 1

Ответ:

вроде бы так, но числа большие

Answer 2

вот,нашла только это

Answer 3

Let's solve each expression step by step:

1. cos²45° - tg²60°:

First, let's evaluate the trigonometric functions involved:

cos(45°) = √2/2

tg(60°) = √3

Now we can substitute these values into the expression:

cos²45° - tg²60° = (√2/2)² - (√3)² = 2/4 - 3 = 1/2 - 3 = -2 1/2

Therefore, cos²45° - tg²60° is equal to -2 1/2.

2. 2cos²60 - sin²30 + sin60ctg60:

Again, let's calculate the trigonometric functions involved:

cos(60°) = 1/2 sin(30°) = 1/2 sin(60°) = √3/2 ctg(60°) = 1/tg(60°) = 1/√3

Now we can substitute these values into the expression:

2cos²60 - sin²30 + sin60ctg60 = 2(1/2)² - (1/2)² + (√3/2)(1/√3) = 2(1/4) - 1/4 + (√3/2)(1/√3) = 1/2 - 1/4 + 1/2 = 2/4 - 1/4 + 2/4 = 3/4

Therefore, 2cos²60 - sin²30 + sin60ctg60 is equal to 3/4.