Question

Вычислите.2 cos 40° - cos 20° - cos 20°​

Answer 1

Ответ:

ответ: cos 40° , т.к. -cos20°-cos20°=-cos40° => 2cos40°-1cos40°=1cos40°. Это тоже самое, что 2x-x=x.

Вроде бы так

Answer 2

To calculate the expression 2cos(40°) - cos(20°) - cos(20°), first, we need to find the values of cos(40°) and cos(20°).

You can use a scientific calculator or trigonometric identities to find these values. Here's how to do it step by step:

Step 1: Find the value of cos(40°) cos(40°) = 0.76604444311 (rounded to 11 decimal places)

Step 2: Find the value of cos(20°) cos(20°) = 0.93969262078 (rounded to 11 decimal places)

Now, plug these values back into the original expression:

2cos(40°) - cos(20°) - cos(20°)

= 2 * 0.76604444311 - 0.93969262078 - 0.93969262078

= 1.53208888622 - 0.93969262078 - 0.93969262078

= 1.53208888622 - 1.87938524156

= -0.34729635534

So, the value of the expression is approximately -0.3473 (rounded to four decimal places).