Animated Solution for Mathematics - Three Dimensional Geometry: Let the line 3x−2=−5y−1=2z+2 lie in the plane x+3y−αz+β=0. Then (α,β) equals
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Visualized Solution
VisualizingtheGeometry
Line: 3x−2=−5y−1=2z+2
Plane: x+3y−αz+β=0
The line lies entirely within the plane.
TheTwoConditions
If a line lies in a plane, two conditions must hold:
1. Every point on the line lies on the plane.
2. The line is perpendicular to the plane's normal vector.
IdentifyingaPointontheLine
From the line equation, a known point is P(2,1,−2).
Since the line is in the plane, P must satisfy the plane equation.
SubstitutingthePoint
Substitute (2,1,−2) into x+3y−αz+β=0:
(2)+3(1)−α(−2)+β=0
DerivingtheFirstEquation
2+3+2α+β=0
2α+β+5=0 (Equation 1)
ExtractingtheVectors
Line direction vector: d=(3,−5,2)
Plane normal vector: n=(1,3,−α)
ThePerpendicularityCondition
The normal vector must be perpendicular to the line's direction.
Therefore, their dot product is zero: d⋅n=0
CalculatingtheDotProduct
(3)(1)+(−5)(3)+(2)(−α)=0
Solvingforα
3−15−2α=0
−12−2α=0
α=−6
Substitutingαback
Substitute α=−6 into Equation 1:
2(−6)+β+5=0
Solvingforβ
−12+β+5=0
β−7=0
β=7
FinalAnswer
The values are α=−6 and β=7.
Final coordinate pair: (α,β)=(−6,7).
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The Sigma Insight: Intersection of a Line and a Plane
Solution Diagram
Analyzing the Setup
To ensure the line defined by
3x−2=−5y−1=2z+2
lies entirely within the plane x+3y−αz+β=0, we must satisfy two geometric constraints.
First, every point on the line must satisfy the equation of the plane. Second, the direction vector of the line must be perpendicular to the normal vector of the plane.
The Point of Contact
From the symmetric form of the line, we can identify a specific point P that lies on the line: P(2,1,−2).
Since the line is contained within the plane, the coordinates of P must satisfy the plane equation x+3y−αz+β=0. Substituting these values, we obtain:
(2)+3(1)−α(−2)+β=0
Simplifying this expression leads to:
2+3+2α+β=0
This yields our first master equation:
2α+β+5=0
The Orthogonality Condition
Next, we identify the direction vector of the line, d=(3,−5,2), and the normal vector of the plane, n=(1,3,−α).
For the line to be parallel to the plane, the dot product of these two vectors must be zero: d⋅n=0.
Calculating the dot product:
(3)(1)+(−5)(3)+(2)(−α)=0
3−15−2α=0
−12−2α=0
Solving for α, we find:
α=−6
Final Calculation
With the value of α determined, we substitute it back into our first master equation to solve for β:
2(−6)+β+5=0
−12+β+5=0
β−7=0
β=7
We have successfully determined the constants. The final values are α=−6 and β=7.