А как kakaть? Решите уравнение (a) f(x)+2f

1
x
= 3x (x
= 0).
(b) f(x) + f

x − 1
x
= 2x (x
= 0).
(c) f(x + y) + f(x − y)=2f(x) cos y

Предыдущий
вопрос Следующий
вопрос

(a)
Let's denote f(x) as y for simplicity. Then, the equation becomes y + 2y = 3x. Simplifying, we get 3y = 3x. Therefore, y = x.
So, the solution to the equation is f(x) = x.

(b)
Let's denote f(x) as y for simplicity. Then, the equation becomes y + y - 1/x = 2x. Simplifying, we get 2y = 2x + 1/x. Therefore, y = x + 1/(2x).
So, the solution to the equation is f(x) = x + 1/(2x).

(c)
This equation is a functional equation that involves trigonometric functions. It doesn't seem to have a simple solution like the previous equations.