cho $\frac{a}{b}$ = $\frac{c}{d}$ . CMR $\frac{ac}{bd }$ = $\frac{a²+ c ² }{b ² +d ²}$ 12/07/2021 Bởi Bella cho $\frac{a}{b}$ = $\frac{c}{d}$ . CMR $\frac{ac}{bd }$ = $\frac{a²+ c ² }{b ² +d ²}$
$\dfrac{a}{b} = \dfrac{c}{d}$ $\Leftrightarrow \dfrac{ac}{bd} = \dfrac{c^2}{d^2} = \dfrac{a^2}{b^2} = \dfrac{a^2 + c^2}{b^2 + d^2}$ Vậy $\dfrac{ac}{bd} = \dfrac{a^2 + c^2}{b^2 + d^2}$ Bình luận
$\dfrac{a}{b} = \dfrac{c}{d}$
$\Leftrightarrow \dfrac{ac}{bd} = \dfrac{c^2}{d^2} = \dfrac{a^2}{b^2} = \dfrac{a^2 + c^2}{b^2 + d^2}$
Vậy $\dfrac{ac}{bd} = \dfrac{a^2 + c^2}{b^2 + d^2}$