Apply componendo-dividendo on $\dfrac{a}{b} = \dfrac{c}{d}$ to get—

Question

Accepted Answer

$\dfrac{a+b}{a-b} = \dfrac{c+d}{c-d}$

Answer

$\dfrac{a+b}{b-a} = \dfrac{c-d}{c+d}$

Answer

$\dfrac{a-b}{a+b} = \dfrac{c+d}{c-d}$

Answer

$\dfrac{a^2+b^2}{a^2-b^2} = \dfrac{c^2-d^2}{c^2+d^2}$

Apply componendo-dividendo on ab=cd\dfrac{a}{b} = \dfrac{c}{d}ba​=dc​ to get—