Question

Sin15°cos7°-cos11°cos79°

Answer 1

Ответ: cos79 = cos(90-11) = sin11

cos11cos79 = cos11sin11 = 0.5sin22

Sin15Cos7-Cos11Cos79 = 0.5sin(15-7) + 0.5sin(15+7) - 0.5sin22 = 0.5sin8

Объяснение:

Answer 2

To evaluate the expression sin(15°)cos(7°) - cos(11°)cos(79°), we need to use trigonometric identities and the values of trigonometric functions for the given angles.

Let's break down the expression and calculate each part individually:

sin(15°) ≈ 0.2588 (rounded to four decimal places) cos(7°) ≈ 0.9925 (rounded to four decimal places) cos(11°) ≈ 0.9816 (rounded to four decimal places) cos(79°) ≈ -0.1461 (rounded to four decimal places)

Now we can substitute these values into the expression:

0.2588 * 0.9925 - 0.9816 * (-0.1461)

Multiply the corresponding values:

≈ 0.2569 + 0.1431

Sum the values:

≈ 0.4000

Therefore, sin(15°)cos(7°) - cos(11°)cos(79°) is approximately equal to 0.4000.