Question

8·cos(-60º) – 2·ctg(-45º) + sin(-30º).

Answer 1

Ответ:

11\2

Розвязание:

8*1/2-2(-1)-1/2; потом 8 и 1/2 скоротится на 2:

4-2*(-1)-1/2;

4+2-1/2 =6-1/2;

11/2 или 5 целих  1\2 или 5,5.

всьо пишется дробом то есть 11/2, 1/2 и так дальше

Answer 2

To calculate the expression 8·cos(-60º) – 2·ctg(-45º) + sin(-30º), we need to evaluate each trigonometric function at its respective angle and then perform the arithmetic operations.

Here are the values of the trigonometric functions at the given angles:

cos(-60º) = cos(60º) = 1/2 (Cosine function is an even function, so cos(-x) = cos(x))

ctg(-45º) = cot(45º) = 1 (Cotangent function is the reciprocal of the tangent function, and cot(45º) = 1)

sin(-30º) = -sin(30º) = -1/2 (Sine function is an odd function, so sin(-x) = -sin(x))

Now, let's substitute these values into the expression:

8·cos(-60º) – 2·ctg(-45º) + sin(-30º) = 8·(1/2) – 2·1 - 1/2

Now, perform the arithmetic operations:

= 4 - 2 - 1/2

= 1/2

So, the result of the expression is 1/2.