External Division (1 Viewer)

[mike12345678]

the points P(5,-10) divides the internal AB, where A is the point (a,2b) and B is a point (3b,-a) externally in the ratio 3:2.

find the values of a and b.

thankyou in advance

 

[mike12345678]

lol thanx solve it

 

[mike12345678]

lol ur big

 

[b3kh1t]

the points P(5,-10) divides the internal AB, where A is the point (a,2b) and B is a point (3b,-a) externally in the ratio 3:2.

find the values of a and b.

thankyou in advance

in the ratio (NB: one of them is negative as it is divided externally)

and

and

by solving simultaneously

substituting this into te other equation we get

 

[nightweaver066]

b3hk1t, you accidently added a minus sign to the y value of point A.

the points P(5,-10) divides the internal AB, where A is the point (a,2b) and B is a point (3b,-a) externally in the ratio 3:2.

find the values of a and b.

thankyou in advance

Remembering that:


and



So now we use the x and y values of P as that is the point that divides the lines, and then you use your two points like so:







Multiplying (1) by 3 and (2) by 2








From (1),

 

[someth1ng]

Alternatively, you can use the formula:
x=[mx2-nx1]/[m-n] which I use as preference since it's an actual formula.

Same does for y but you just change the x to y.

 

[mike12345678]

yea thats the one i use.

thanx for all ur help

 

[rainydays]

How do you know which part of the ratio is negative. Whether it is the 3 or the 2? Or doesn't it matter?

 

[nightweaver066]

How do you know which part of the ratio is negative. Whether it is the 3 or the 2? Or doesn't it matter?

It does not matter. As long as you let either side be a negative. I chose to let the 2 be the negative as it would make the denominator in to a nice positive 1 which is easier to work with.

 

[Aesytic]

either ratio can be negative; either -3:2 or 3:-2 but both can't be negative i.e. -3:-2

 

[rainydays]

Thanks guys