Question

tính A = \(\dfrac{a}{b+c}+\dfrac{b}{a+c}+\dfrac{c}{a+b}\) biết \(\dfrac{a}{b+c}=\dfrac{b}{a+c}=\dfrac{c}{a+b}\)

Answer 1

A = \(\dfrac{a}{b+c}+\dfrac{b}{a+c}+\dfrac{c}{a+b}\)

Mà \(\dfrac{a}{b+c}=\dfrac{b}{a+c}=\dfrac{c}{a+b}\)

\(\Rightarrow\)A = a + b + c (với a, b, c \(\in\) R