Animated Solution for Mathematics - Straight Lines: The distance of the point (2,3) from the line 2x−3y+28=0, measured parallel to the line 3x−y+1=0, is equal to
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Visualized Solution
Visualizing the Problem
Given Point: A(2,3)
Target Line L1:2x−3y+28=0
Direction Line L2:3x−y+1=0
Goal: Find distance r from A to L1 measured parallel to L2.
Finding the Direction Angle θ
Equation of direction line L2: 3x−y+1=0
Rearranging to y=mx+c: y=3x+1
Slope m=tanθ=3
Therefore, θ=60∘
The Parametric Tool
Using Parametric Form for point P at distance r from A(2,3)
x=x1+rcosθ
y=y1+rsinθ
Raw Setup for Point P
Substitute A(2,3) and θ=60∘
x=2+rcos60∘=2+2r
y=3+rsin60∘=3+23r
Let this point be P(x,y)
Substitution into Target Line
Point P(2+2r,3+23r) lies on L1
Equation of L1: 2x−3y+28=0
Substitute P into L1:
2(2+2r)−3(3+23r)+28=0
Expanding the Equation
Expanding the terms carefully:
2(2)+2(2r)−3(3)−3(23r)+28=0
4+r−9−233r+28=0
Grouping and Simplifying
Combine constant terms: 4−9+28=23
Combine r terms: r−233r=r(1−233)
Simplified Equation: 23+r(1−233)=0
Isolating r
Take common denominator for r term: r(22−33)
Move constant to RHS: r(22−33)=−23
Solve for r: r=2−33−46
Absorb negative sign: r=33−246
Rationalizing the Denominator
Multiply numerator and denominator by conjugate: 33+2
r=33−246×33+233+2
Denominator becomes: (33)2−(2)2=27−4=23
r=2346(33+2)
The Final Answer
Simplify the fraction: 2346=2
r=2(33+2)
Expand to get final form: r=63+4
Rearranging gives: r=4+63
This matches Option 3.
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The Sigma Insight: Various Forms of Equations of a Line
Solution Diagram
The Geometry of the Path
Imagine you are standing at the point A(2,3) on a vast coordinate plane. You have a destination—a target line defined by the equation 2x−3y+28=0.
If you were a bird, you would fly the shortest path, dropping perpendicularly onto the line. But you are not a bird; you are a traveler constrained to a specific road. You must walk parallel to the line 3x−y+1=0.
This constraint changes everything. It turns a simple distance problem into a beautiful exercise in parametric geometry.
Phase 1
Finding Your Compass
Before we take a single step, we must know our heading. The line that dictates our direction is 3x−y+1=0.
To understand its tilt, we rearrange it into the slope-intercept form, y=mx+c. This gives us y=3x+1. The slope m is 3.
We know that the slope of a line is the tangent of the angle θ it makes with the positive x-axis. So, tanθ=3. Recalling our trigonometry, we identify that θ=60∘. Our path is set; we are walking at a 60∘ angle relative to the horizontal.
Phase 2
The Parametric Bridge
Now, how do we mathematically describe our journey? We use the parametric form of a straight line. If we start at (x1,y1) and walk a distance r at an angle θ, any point P(x,y) on our path is given by the elegant equations:
x=x1+rcosθ
y=y1+rsinθ
Substituting our starting point A(2,3) and our angle θ=60∘, we get:
x=2+rcos60∘=2+2r
y=3+rsin60∘=3+23r
This is the bridge between our movement and the target line. Every point P on our path is now defined by the distance r we have traveled.
Phase 3
The Intersection
Our destination is the target line 2x−3y+28=0. Since our point P must lie on this line, its coordinates must satisfy the equation.
We substitute our parametric expressions for x and y into the line equation:
2(2+2r)−3(3+23r)+28=0
Now, we expand carefully. Precision is key here. We get:
4+r−9−233r+28=0
Grouping the constants and the r-terms, we have:
(4−9+28)+r(1−233)=0
23+r(22−33)=0
Phase 4
The Final Calculation
We are almost there. Isolating r, we find:
r(22−33)=−23
r=2−33−46=33−246
To finish, we rationalize the denominator by multiplying the numerator and denominator by the conjugate, 33+2:
r=(33)2−2246(33+2)=27−446(33+2)=2346(33+2)
Watch the magic happen: 46 divided by 23 is exactly 2. Thus, r=2(33+2)=63+4.
We have arrived. The distance is 4+63. It is a beautiful result, born from the simple act of following a path.