00:01
In this video, we want to write the equation of a plane, and we know a point that it passes through and a line that it's perpendicular to.
00:08
So in general, if you can use the standard form of the equation, where we'll have a times x minus x not plus b times y minus y not plus c times z minus z not is equal to zero, where the point that it passes through, is x -not, y -not, z -not, and then it's perpendicular to the vector containing a, b, c.
00:46
So this point that the plane passes through is already given as 1 ,0, comma, 7.
00:53
So then in order to plug in, all we need to do is find the normal vector.
00:57
And we know our particular plane is perpendicular to a line that was given by a parametric equation.
01:05
X is equal to 5 t, y is equal to 5 minus t, and z is equal to 3 plus 4 t.
01:19
So if we wanted to write the equation in terms of x, y, and z, let's see.
01:24
So x is equal to 5t, so t is equal to x over 5.
01:32
So then we have y is equal to 5 minus x over 5, or just to make the fractions go and multiply everything 3 by 5.
01:41
We get 5y is equal to 25 minus x.
01:47
And then z is equal to 3 plus 4 times x over 5, subbing in x for t.
01:56
Multiplying through by 5, we get 5 z is equal to 15 plus 4x.
02:14
We can add these two together.
02:16
So we get 5y plus 5 z is equal to 40 minus 4x.
02:24
X plus 3x, move the x over to the other side.
02:29
So 3x plus 5y plus 5z is equal to 40.
02:39
All right.
02:39
So from this standard equation, we see that the normal vector to this line is negative 3, 5, and 5.
02:51
Just taking the coefficients...