Find the coordinates of D which lies on the vector BC

In summary, the conversation involves finding the equation of a line from points B(-8,-3) to C(4,6), with point A assumed to be at the origin. The suggestion is made to start by drawing a diagram of the two vectors AC and AB, and using the "Attach files" link to upload it. The equation of the line can be found by finding the slope and using the point-slope form, and then the distance formula can be used to find point D, which is 5/11th of the way from B to C. The problem can also be solved using simple geometry and proportionality, but a diagram is needed for further assistance.
  • #1
MathMan2022
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Homework Statement
Lets image we have two vectors AC = <4,6> and AB = <-8,-3> then find a point D which lies on the vector BC which satisfies that |BD|/|CD| = 5/6 ??
Relevant Equations
|BD| = 5/6 |CD|
Not sure on howto proceed here?
 
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  • #2
You know that you need to show your work before we can offer tutorial help.

Perhaps start by drawing a diagram of those two vectors to see if it gives you some ideas? You can use the "Attach files" link below the Edit window to upload a PDF or JPEG of your sketch...
 
  • #3
That I can figure out is that if I write <DB>=5/6<DC> then
<OD>-<OB>=5/6*(<OD>-<OC>)

But don't know howto proceed from there?
 
  • #4
MathMan2022 said:
But don't know howto proceed from there?
Find the equation of the line from B(-8, -3) to C(4, 6). I am assuming that point A is at the origin. You can do this by finding the slope of the line, and then the point-slope form of the equation of a line.
Once you have the equation of the line, use the distance formula to find point D. It would be at a the point that is 5/11th of the way from B to C.
 
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  • #5
MathMan2022 said:
Homework Statement:: Lets image we have two vectors AC = <4,6> and AB = <-8,-3> then find a point D which lies on the vector BC which satisfies that |BD|/|CD| = 5/6 ??
Relevant Equations:: |BD| = 5/6 |CD|

Not sure on howto proceed here?
Although it may not the required/intended method, note that the problem can easily be done with only simple geometry and proportionality.

But you haven't yet posted a diagram so I can't help more.
 
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FAQ: Find the coordinates of D which lies on the vector BC

How do you find the coordinates of point D on the vector BC?

To find the coordinates of point D on the vector BC, you need to know the coordinates of points B and C. If D divides the vector BC in the ratio m:n, you can use the section formula: D = [(m*C_x + n*B_x)/(m+n), (m*C_y + n*B_y)/(m+n)], where B(x1, y1) and C(x2, y2).

What is the section formula?

The section formula is a mathematical formula used to find the coordinates of a point that divides a line segment joining two given points in a specified ratio. For a point D dividing the line segment BC in the ratio m:n, the coordinates are given by: D = [(m*C_x + n*B_x)/(m+n), (m*C_y + n*B_y)/(m+n)].

What if point D is the midpoint of vector BC?

If point D is the midpoint of vector BC, the ratio m:n is 1:1. Therefore, the coordinates of D can be found using the midpoint formula: D = [(B_x + C_x)/2, (B_y + C_y)/2].

How do you find the coordinates if D lies outside the segment BC?

If point D lies outside the segment BC, you can still use the section formula, but the ratio m:n will be negative. For example, if D divides BC externally in the ratio m:n, the coordinates are given by: D = [(m*C_x - n*B_x)/(m-n), (m*C_y - n*B_y)/(m-n)].

Can you provide an example calculation for finding point D?

Sure! Let's say B has coordinates (2, 3) and C has coordinates (8, 7), and D divides BC in the ratio 2:3. Using the section formula:D = [(2*8 + 3*2)/(2+3), (2*7 + 3*3)/(2+3)] = [(16 + 6)/5, (14 + 9)/5] = [22/5, 23/5] = (4.4, 4.6).

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