Hi everyone,

I know that i am just being lazy or blind or both but the last question on this sheet eludes me.

Can someone help please.

140211 Tom's question.jpg

I know that i am just being lazy or blind or both but the last question on this sheet eludes me.

Can someone help please.

140211 Tom's question.jpg

Melody Feb 11, 2014

#1**0 **

You need to show that T and U have the same y coordinate.

T has y coordinate apq

U has y coordinate -apr

but if you look at the coordinates of P and Q and note that PQ is perpendicular to the axis of the parabola then it should be clear that q = -r

so both T and U have y coordinates apq and thus TU is horizontal and thus perpendicular to the vertical parabola axis.

T has y coordinate apq

U has y coordinate -apr

but if you look at the coordinates of P and Q and note that PQ is perpendicular to the axis of the parabola then it should be clear that q = -r

so both T and U have y coordinates apq and thus TU is horizontal and thus perpendicular to the vertical parabola axis.

Rom Feb 11, 2014

#2**+5 **

Of course, thanks Rom, much appreciated.

Rom:You need to show that T and U have the same y coordinate.

T has y coordinate apq

U has y coordinate -apr

but if you look at the coordinates of P and Q and note that PQ is perpendicular to the axis of the parabola then it should be clear that q = -r

so both T and U have y coordinates apq and thus TU is horizontal and thus perpendicular to the vertical parabola axis.

Of course, thanks Rom, much appreciated.

Melody Feb 11, 2014