If O is the origin and Q is a variable point on y2 = x, Find the locus of the mid-point of OQ.
Key points to solve the problem:
• Idea of section formula- Let two points A(x1,y1) and B(x2,y2) forms a line segment. If a point C(x,y) divides line segment AB in the ratio of m:n internally, then coordinates of C is given as:
C = when m = n =1 , C becomes the midpoint of AB and C is given as C =
How to approach: To find the locus of a point we first assume the coordinate of the point to be (h, k) and write a mathematical equation as per the conditions mentioned in the question and finally replace (h, k) with (x, y) to get the locus of the point.
Let the coordinates of a point whose locus is to be determined to be (h, k). Name the moving point to be C
As, coordinate of mid point is (h,k) {by our assumption},
Let Q(a,b) be the point such that Q lies on curve y2 = x
b2 = a ……equation 1
According to question C is the midpoint of OQ
∵ C = ⇒ C =
∴
Similarly,
Putting values of a and b in equation 1,we have:
Replace (h,k) with (x,y)
Thus, the locus of a point is: ….ans