Practice question · Numerical answer
The plane 2x - 3y + z = 7 has normal vector (a, b, c). What is b?
Hints
- The normal vector is read straight off the coefficients of x, y and z.
- Keep the sign that appears in the equation.
Show the answer
-3
Why
The normal is (2, -3, 1), so b = -3. The constant 7 plays no part in the direction, it only shifts the plane along that normal. Dropping the minus sign would give a vector pointing into a different half of space.
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