Proof: the square of a divided by B + C plus the square of B divided by a + C plus the square of C divided by a + B is greater than or equal to two parts of a + B + C

Proof: the square of a divided by B + C plus the square of B divided by a + C plus the square of C divided by a + B is greater than or equal to two parts of a + B + C

I can't understand it. What's written is (a * A / B + C) + (b * B / A + C) + (c * C / A + b) > = (a + B + C) / 2 good proof: for the left, reduce the denominator of the three fractions on the left to a + B + C, left > = (a * A / A + B + C) + (b * B / A + B + C) + (c * C / A + B + C) = (a * a + b * B + C) / (a + B + C) because a * a + b * B + C > = (a + B +