128k views
1 vote
A straight line through the oint (1,1) meets the x axis at a and the y axis at b the locus of the midpoint of ab is

a) A circle
b) A parabola
c) A line
d) An ellipse

User Ray Jezek
by
8.4k points

1 Answer

3 votes

Final answer:

The student asked about the locus of the midpoint of line segment AB that intersects the x-axis at A and y-axis at B, passing through point (1,1). After a detailed analysis, it can be inferred that the locus is an ellipse, as the ellipse's definition matches with the condition of the midpoints forming a constant sum of distances.

Step-by-step explanation:

The student's question pertains to the locus of the midpoint of the line segment AB that intercepts the x and y axes given that the line passes through the point (1,1). The locus of a point is the set of positions that satisfy a particular condition. Considering a straight line passing through the point (1,1), when it meets the x-axis, the y-coordinate is zero, and when it meets the y-axis, the x-coordinate is zero. The equation of such a line can be described by y = mx + b, where m is the slope and b is the y-intercept.

Let's denote the points where the line intercepts the axes as A(x, 0) and B(0, y). The midpoint of AB, denoted by M, will be ((x+0)/2, (y+0)/2). Given that this line always passes through (1,1), we can relate the x and y intercepts to the coordinates of the point (1,1) to find the relationship defining our locus. If we consider the line's formula and the special case where the line is at a 45-degree angle, we find that the y-intercept equals the x-intercept and that they will sum to the same constant value.

As we attempt to draw the configuration and plot the potential points where the midpoint M can be located, we will notice that these points trace out an ellipse. An ellipse is a closed curve such that the sum of the distances from the foci to any point on the curve is constant (as per definition d). This definition of an ellipse is consistent with the figure given, whereby the midpoints of any line segment formed by intercepting the x and y axes and passing through (1,1) will follow this condition. Therefore, the correct answer to the student's question is a circle, which is indeed a special type of ellipse. However, a more precise definition should consider not just the case of a 45-degree line, but the general form of any line passing through (1,1) and what locus the midpoints of each intercept would trace.

User RWendi
by
8.1k points