Question

Answer 1

3.

Áp dụng t/c dtsbn:

\(\dfrac{a}{c}=\dfrac{c}{b}=\dfrac{a^2}{c^2}=\dfrac{c^2}{b^2}=\dfrac{a^2+c^2}{b^2+c^2}\left(1\right)\)

Ta có \(\dfrac{a}{c}=\dfrac{c}{b}\Leftrightarrow ab=c^2\Leftrightarrow\dfrac{ab}{b^2}=\dfrac{c^2}{b^2}\Leftrightarrow\dfrac{a}{b}=\dfrac{c^2}{b^2}\left(2\right)\)

\(\left(1\right)\left(2\right)\Leftrightarrow\dfrac{a}{b}=\dfrac{a^2+c^2}{b^2+c^2}\left(=\dfrac{c^2}{b^2}\right)\)

Answer 2

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