Analyzing the Setup
Imagine you are standing in a vast, empty 3D space. You have a flat, infinite sheet of paper—a plane—defined by the equation:
Now, imagine a laser beam, a line defined by the symmetric equations:
Our mission is to find the exact point where this laser meets the paper. This is a fundamental problem of spatial intersection.
The Parametric Bridge
To find this point, we need a way to describe every single location on that laser beam. We use the parametric form by setting the line's ratios equal to a parameter λ:
This single variable λ acts as a coordinate tracker. If we know λ, we know exactly where we are on the line.
Rearranging these, we get the coordinates of any point on the line in terms of λ:
This triplet (2λ+4,2λ+5,λ+3) is our key to the intersection.
The Collision Point
The plane acts as a constraint; it demands that the sum of the coordinates of any point on it must be 2. We take our general point from the line and force it to satisfy the plane's equation:
Grouping the terms, we obtain:
Solving for λ is straightforward:
This value, λ=−2, is the specific parameter at which our laser hits the plane. Substituting λ=−2 back into our parametric equations gives us the intersection point P:
x=2(−2)+4=0
y=2(−2)+5=1
z=(−2)+3=1
Thus, our point of intersection is P(0,1,1).
The Final Verification
The problem asks us to identify which of the given lines passes through this point P(0,1,1). We test the options by substituting x=0,y=1,z=1 into the provided line equations.
Consider the line:
Substituting our point P(0,1,1) into this equation:
10−1=−1,21−3=−1,−51+4=−1
Since all three ratios equal −1, the point P(0,1,1) lies perfectly on this line. We have successfully navigated the 3D landscape to confirm the intersection.