It is known that a, B and C are the three sides of a triangle, Verification: C / (a + b) + A / (B + C) + B / (c + a)

It is known that a, B and C are the three sides of a triangle, Verification: C / (a + b) + A / (B + C) + B / (c + a)

Explain a conclusion before proof
Add sugar in the sugar water, it will become sweet, indicating that the concentration of sugar water has increased
We can draw a conclusion from it
A/B