Calc: finding an equation

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In summary, To find the equation of a plane passing through the point (1,3,1) and containing the line x=t, y=t, z=-2+t, you need two distinct directional vectors and one point on the plane. You can find the directional vector of the line by using a point on the line and the given point. The equation of the plane will have the form P = (x,y,z) + sd1 + td2, where s and t are scalar multiples and d1 and d2 are the directional vectors. There are multiple solutions to this problem.
  • #1
kid2
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how do i work this?

find an equation for the plane that passes through the point (1,3,1) and contains the line x=t,y=t,z=-2+t

would the line equation be -2i+t(i+j+k)? and then would that mean that the direction or normal vector for the plane be i+j+k? and then what do you do? i have the answer and i can't get it...
 
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  • #2
to find the equation of a plane you need to have TWO distinct directional vectors and one point the plane passes through

you have been told that it contains the line - what is the directional vector of that line
you need one more directional vector - a vector between the line and the point will give you this. Pick a point on the given line and find the vector between this point and the given point.
the equation of the plane will look like this

[tex] P = (x,y,z) + sd_{1} + td_{2} [/tex]
where s and t are scalar mutliples, d1 and d2 the directional vectors and x y z is the point

p.s. there are many possible answers
 
  • #3


To find the equation of a plane, we need to use the point and normal vector form of the equation, which is (x-x0)⋅n=0, where x0 is a point on the plane and n is the normal vector.

First, we can find the normal vector by taking the cross product of the direction vectors of the given line, which would be (1,1,0) and (0,0,1). This gives us the normal vector (1,-1,1).

Next, we can plug in the given point (1,3,1) and the normal vector into the equation, which gives us (x-1, y-3, z-1)⋅(1,-1,1)=0.

Simplifying this equation, we get x-y+z=3 as the equation of the plane.

In terms of the line equation that you have, it would be helpful to use the parametric form of the line, which is x=1+t, y=3+t, z=-2+t. Then, using the same process as above, we can find the normal vector and ultimately the equation of the plane.

I hope this helps clarify the process for finding the equation of a plane passing through a given point and containing a given line.
 

1. How do I find the equation for a given set of points?

The most common method for finding an equation for a set of points is to use the slope-intercept form: y = mx + b. First, calculate the slope (m) by dividing the change in y coordinates by the change in x coordinates. Then, plug in one of the points to solve for b. Finally, write the equation in slope-intercept form using the calculated values.

2. Can I use other forms besides slope-intercept to find the equation?

While slope-intercept form is the most commonly used form, you can also use point-slope form or standard form to find the equation. Point-slope form is useful when you have one point and the slope, while standard form is useful for graphing and finding the x and y intercepts.

3. What if I have more than two points?

If you have more than two points, you can still use the slope-intercept form to find the equation. Choose any two points and calculate the slope, then use one of the points to solve for b. If the equation doesn't match the remaining points, you may have made a calculation error or the points may not actually lie on a straight line.

4. How do I find the equation for a line that is not straight?

If the points do not lie on a straight line, then you cannot use a linear equation to represent them. Instead, you may need to use a quadratic or other non-linear equation to model the data. This can be done using regression analysis or other curve-fitting methods.

5. Can I use a calculator or computer program to find the equation for me?

Yes, there are many calculators and computer programs available that can find the equation for a set of points. These programs use advanced algorithms and regression analysis to find the best-fitting equation for the data. However, it is still important to understand the process and be able to calculate the equation by hand.

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