Question

The diameter of a circle has endpoints at (-4,2) and (4,-4). What is an equation of the circle?

Answer 1

well diameter form of circle is:
\[(x-x1)(x-x2)+(y-y1)(y-y2)=0 \] where (x1,y1) and (x2,y2) are end points of diameter line.
alternatively you can find radius from the end points of diameter by using distance formula and also its mid point (h,k) by mid point formula. And you can use standard equation of circle:
\[(x-h)^2+(y-k)^2 =r^2\]

Answer 2

hmm, ive never seen the diameter form before. thats nice to know :)

Answer 3

Thanks. I don't get it at all and we have a huge test on it today.