Question Number 29231 by Tinkutara last updated on 05/Feb/18
Answered by ajfour last updated on 05/Feb/18
$${eq}.\:{of}\:{chord}\:{of}\:{contact}\:{to}\:{circle} \\ $$$$\boldsymbol{{x}}^{\mathrm{2}} +\boldsymbol{{y}}^{\mathrm{2}} =\mathrm{1}\:\:\:{from}\:\:\left({x}_{\mathrm{1}} ,\:{y}_{\mathrm{1}} \right)\:\:{is} \\ $$$${xx}_{\mathrm{1}} +{yy}_{\mathrm{1}} =\mathrm{1} \\ $$$${given}\:{eq}.\:{of}\:{chord}\:{of}\:{contact}\:{is} \\ $$$$\:\mathrm{2}{x}+\mathrm{2}{y}=\mathrm{1} \\ $$$${so}\:\:{upon}\:{comparison} \\ $$$$\:\:{A}\left({x}_{\mathrm{1}} ,\:{y}_{\mathrm{1}} \right)\equiv\:\left(\mathrm{2},\:\mathrm{2}\right)\:. \\ $$
Commented by Tinkutara last updated on 05/Feb/18
But how this equation is derived? Can this be solved without learning this formula?