Question #42cd3

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Answer 1 · 2016-02-10T13:49:44

If $F != f_1$

$f_2=(Ff_1)/(f_1-F)$

If $F != f_1$ (to avoid dividing by $0$ )

$F = (f_1f_2)/(f_1+f_2)$

$=>F(f_1+f_2)=f_1f_2$

$=>Ff_1 + Ff_2 = f_1f_2$

$=>Ff_2-f_1f_2 = -Ff_1$

$=>f_2(F-f_1)=-Ff_1$

$:.f_2=-(Ff_1)/(F-f_1)=(Ff_1)/(f_1-F)$