- #1
Bashyboy
- 1,421
- 5
Homework Statement
Find the value of k such that no solutions are shared between the planes
x + 2y + kz = 6
and
3x + 6y + 8z = 4
Homework Equations
The Attempt at a Solution
I figured that if I calculated [itex]\vec{n_1} \times \vec{n_2} = \vec{0}[/itex], and then take the magnitude of this vector equation, I could procure the correct k-value.
Here are some parts of my work:
[itex]\vec{n_1} \times \vec{n_2} = (16-6k)\hat{i} + (3k-8)\hat{k}[/itex]
[itex]0=320 -240k + 39k^2[/itex]
[itex]k = \frac{120 \pm 8 \sqrt{30}}{39}[/itex]
When I graphed the two planes, it was quite conspicuous that the two planes were not parallel.
What is wrong with my work and reasoning?