Question

Cos^2 45+sin30-ctg^2 30

Answer 1

Применены табличные значения тригонометрических функций

Answer 2

Let's simplify each term one by one:

cos^2 45 = 1/2 (since cos 45 = sqrt(2)/2)

sin 30 = 1/2 (since sin 30 = 1/2)

ctg^2 30 = (cos 30 / sin 30)^2 = (sqrt(3)/2 / 1/2)^2 = (sqrt(3))^2 = 3

Substituting these values in the given expression, we get:

cos^2 45 + sin 30 - ctg^2 30 = 1/2 + 1/2 - 3 (using the values we obtained above) = 0 - 3 = -3

Therefore, cos^2 45 + sin 30 - ctg^2 30 = -3.