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Question-91933




Question Number 91933 by liki last updated on 03/May/20
Commented by liki last updated on 03/May/20
...please mr w help me ,emergency!<
$$…\mathrm{please}\:\mathrm{mr}\:\mathrm{w}\:\mathrm{help}\:\mathrm{me}\:,\mathrm{emergency}!< \\ $$
Commented by liki last updated on 03/May/20
Qn 11
$$\mathrm{Qn}\:\mathrm{11} \\ $$
Answered by mr W last updated on 03/May/20
Commented by mr W last updated on 03/May/20
say the line parallel to y−axis is  x=u  intersection with y=x^2  at P:  x_P =u, y_P =u^2   intersection with y=x+2 at Q:  x_Q =u, y_Q =u+2  mid−point of PQ is M:  x_M =u, y_M =((y_P +y_Q )/2)=((u^2 +u+2)/2)=((x_M ^2 +x_M +2)/2)  i.e. the locus of point M is  y=((x^2 +x+2)/2)  which is also a parabola.
$${say}\:{the}\:{line}\:{parallel}\:{to}\:{y}−{axis}\:{is} \\ $$$${x}={u} \\ $$$${intersection}\:{with}\:{y}={x}^{\mathrm{2}} \:{at}\:{P}: \\ $$$${x}_{{P}} ={u},\:{y}_{{P}} ={u}^{\mathrm{2}} \\ $$$${intersection}\:{with}\:{y}={x}+\mathrm{2}\:{at}\:{Q}: \\ $$$${x}_{{Q}} ={u},\:{y}_{{Q}} ={u}+\mathrm{2} \\ $$$${mid}−{point}\:{of}\:{PQ}\:{is}\:{M}: \\ $$$${x}_{{M}} ={u},\:{y}_{{M}} =\frac{{y}_{{P}} +{y}_{{Q}} }{\mathrm{2}}=\frac{{u}^{\mathrm{2}} +{u}+\mathrm{2}}{\mathrm{2}}=\frac{{x}_{{M}} ^{\mathrm{2}} +{x}_{{M}} +\mathrm{2}}{\mathrm{2}} \\ $$$${i}.{e}.\:{the}\:{locus}\:{of}\:{point}\:{M}\:{is} \\ $$$${y}=\frac{{x}^{\mathrm{2}} +{x}+\mathrm{2}}{\mathrm{2}} \\ $$$${which}\:{is}\:{also}\:{a}\:{parabola}. \\ $$
Commented by liki last updated on 04/May/20
...thank you sir , be blessed !
$$…\mathrm{thank}\:\mathrm{you}\:\mathrm{sir}\:,\:\mathrm{be}\:\mathrm{blessed}\:! \\ $$

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