Equations of Planes — Question 1

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Question 1

Find scalar and vector equations of the plane through P0=(2,−1,3)P_0=(2,-1,3) with normal vector n→=⟨4,2,−1⟩\vec n=\left\langle 4,2,-1\right\rangle. Find its intercepts with the coordinate axes.

Original worksheet page 1: question and worked solution for 6-3-001
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Question 1 – Solution

Strategy Use n→⋅(r→−r→0)=0\vec n\cdot(\vec r-\vec r_0)=0, then set two coordinates equal to zero for each intercept.

See the diagram in the original worksheet below.

Equations The vector equation is ⟨4,2,−1⟩⋅⟨x−2,y+1,z−3⟩=0\left\langle 4,2,-1\right\rangle\cdot\left\langle x-2,y+1,z-3\right\rangle=0, which simplifies to 4x+2y−z=3\boxed{4x+2y-z=3}.

Intercepts The xx-, yy-, and zz-intercepts are (3/4,0,0),(0,3/2,0),(0,0,−3).\boxed{(3/4,0,0),\quad(0,3/2,0),\quad(0,0,-3)}.

Verification Substituting P0P_0 gives 8−2−3=38-2-3=3, and each intercept satisfies the scalar equation.

Original worksheet page 2: question and worked solution for 6-3-001

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