Posted by Joshua on .
Hi guys,
In the question "It is given that P (0, 3), Q(7, 5), R(9, 2) and S are vertices of a square. A circle A passes through the points P, Q, R and S. Find the equation of this circle. Hence or otherwise find the equation of circle B which is the image of A under the reflection about y – axis."
Can someone help me with the part hence or otherwise? I've found that the equation of the circle is x^2 + y^2 9x y 6 =0
Thanks =)

Math 
drwls,
Assuming your answer is correct, it can be written
(x  9/2)^2 + (y  1/2)^2 = 106/4
(check my numbers)
The reflection about the y axis would be
(x + 9/2)^2 + (y  1/2)^2 = 106/4 
Math 
Joshua,
Hi drwls,
Just wondering, does the word "under" in the question influence the question at all?
Thanks for your reply! =) 
Math 
drwls,
In this mathematics context, "Under the reflection about (an axis)" is the same as saying "after a reflection about (an axis)"
Mathematicions often us the preposition "under" to indicate carrying out an operation. It does not mean "below" in this case. 
Math 
Joshua,
Thanks drwls for the good explanation =)

Math 
mina,
jack has 3/4 of a dollar. Maxwell has 1/10 of a dollar. Do they have more or less than $1.oo in all?