Question:medium

The point on the straight line \(y = 2x + 11\) which is nearest to the circle \(16(x^2 + y^2) + 32x - 8y - 50 = 0\), is

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Nearest point from a line to a circle is always the foot of perpendicular from the center to the line.
Updated On: May 21, 2026
  • \(\left(\frac{9}{2},2\right)\)
  • \(\left(\frac{9}{2},-2\right)\)
  • \(\left(-\frac{9}{2},2\right)\)
  • \(\left(-\frac{9}{2},-2\right)\)
Show Solution

The Correct Option is C

Solution and Explanation

The equation of the circle given is:

\(16(x^2 + y^2) + 32x - 8y - 50 = 0\)

First, simplify the circle's equation:

  • Divide the entire equation by 16 to simplify:

Next, convert this into the standard circle form \((x - h)^2 + (y - k)^2 = r^2\) by completing the square.

  • For \(x\)-terms: \(x^2 + 2x = (x + 1)^2 - 1\)
  • For \(y\)-terms: \(y^2 - \frac{1}{2}y = (y - \frac{1}{4})^2 - \frac{1}{16}\)

Substitute these adjustments back into the equation:

\((x + 1)^2 - 1 + (y - \frac{1}{4})^2 - \frac{1}{16} - \frac{25}{8} = 0\)

Combine and simplify the constant terms:

\((x + 1)^2 + (y - \frac{1}{4})^2 = \frac{100}{64} = \frac{25}{16}\)

Now, the standard form of the circle is:

\((x + 1)^2 + (y - \frac{1}{4})^2 = \left(\frac{5}{4}\right)^2\)

This shows a circle centered at \((-1, \frac{1}{4})\) with radius \(\frac{5}{4}\).

To find the point on the line \(y = 2x + 11\) closest to the circle's center, use the distance formula. The distance \(d\) from a point \((x_1, y_1)\) to a line \(ax + by + c = 0\) is:

\(d = \frac{|ax_1 + by_1 + c|}{\sqrt{a^2 + b^2}}\)

For the line \(y = 2x + 11\) or (-1, \frac{1}{4}) into the distance formula: \(d = \frac{|2(-1) - 1/4 + 11|}{\sqrt{4 + 1}}\) 

To find the specific point on the line, considering the perpendicular slope to \(y = 2x + 11\), an optimal approach involves finding such that the line from \((-1, \frac{1}{4})\) to the point is perpendicular.

The perpendicular slope is \(\frac{-1}{2}\).

  • Set up the equation of the line:
  • Substitute in \(y = 2x + 11\) to solve for intersection:

Solving simultaneous equations:

  • From step solutions:
  • Simplifying yields:

Thus, the point on the line \(y = 2x + 11\) nearest to the circle is:

\(\left(-\frac{9}{2}, 2\right)\)

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