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The shortest distance of the point (12,1)\left(\frac{1}{2}, 1\right) from the curve y=∣x−1∣+∣x+1∣y=|x-1|+|x+1| is

Solution

✅ Correct Option: 1

We need to find the shortest distance from the point (12,1)\left(\frac{1}{2}, 1\right) to the curve y=∣x−1∣+∣x+1∣y = |x-1| + |x+1|.


To sketch y=∣x−1∣+∣x+1∣y = |x-1| + |x+1|, we need to analyze where each absolute value expression changes sign:

∣x−1∣|x-1| changes at x=1x = 1

∣x+1∣|x+1| changes at x=−1x = -1

This gives us three intervals to consider:

For x<−1x < -1:

Both (x−1)(x-1) and (x+1)(x+1) are negative

So ∣x−1∣=−(x−1)=−x+1|x-1| = -(x-1) = -x+1 and ∣x+1∣=−(x+1)=−x−1|x+1| = -(x+1) = -x-1

Therefore: y=(−x+1)+(−x−1)=−2xy = (-x+1) + (-x-1) = -2x

For −1≤x<1-1 \leq x < 1:

(x−1)(x-1) is negative, (x+1)(x+1) is non-negative

So ∣x−1∣=−(x−1)=−x+1|x-1| = -(x-1) = -x+1 and ∣x+1∣=x+1|x+1| = x+1

Therefore: y=(−x+1)+(x+1)=2y = (-x+1) + (x+1) = 2

For x≥1x \geq 1:

Both (x−1)(x-1) and (x+1)(x+1) are non-negative

So ∣x−1∣=x−1|x-1| = x-1 and ∣x+1∣=x+1|x+1| = x+1

Therefore: y=(x−1)+(x+1)=2xy = (x-1) + (x+1) = 2x


y={−2xif x<−1 2if −1≤x<1 2xif x≥1y = \begin{cases} -2x & \text{if } x < -1 \ 2 & \text{if } -1 \leq x < 1 \ 2x & \text{if } x \geq 1 \end{cases}

This creates a V-shaped curve with a flat bottom segment.


The point (12,1)\left(\frac{1}{2}, 1\right) has x-coordinate 12\frac{1}{2}, which falls in the interval [−1,1)[-1, 1).

In this interval, the curve is simply y=2y = 2 (a horizontal line).

Since our point is at (12,1)\left(\frac{1}{2}, 1\right) and the curve directly above it is at (12,2)\left(\frac{1}{2}, 2\right), the shortest distance is the vertical distance between these points.


Distance = ∣2−1∣=1|2 - 1| = 1

The horizontal segment y=2y = 2 for −1≤x<1-1 \leq x < 1 is the closest part of the curve to our point. Any other point on the slanted portions of the curve would be farther away. The perpendicular distance from a point to a horizontal line is simply the difference in y-coordinates.

Therefore, the shortest distance is 1.

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