Recent content by geoff18

Homework Statement Let A, B be points in R3 with position vectors a:(7,-2,3) b:(1,-5,0) Let Q be the point on AB such that AQ= 2/3 AB Find q, the position vector of Q Homework Equations The back of the book says the answer is: (2,-3,-1) The Attempt at a Solution First, I found...

Hi Thanks for the picture azizlwl, so using tri functions, i assume that the point will be: (5cos(45), ((5*sin(45))+3))

so according to this then: Origin: (0,0) First point: (0,3) Second Point: (5,8) [Moved move 5 units right/east AND 5 units up/north] so the distance should be 5^2+8^2=25+64=89 =sqrt(89) =>9.43(approx)? The answer states: 7.43 tho? Did I do something wrong?

so the co-ordinate of the third point will be ((sqrt of 25)/2)),((sqrt of 25)/2))+3))

Hi Azizlwl, thanks for the reply. How would I write the co-ordinates of 5 units moving in north east direction? Would i need to use pythag's theorm to calculate the co-ordinates? thanks

Hi thanks for the prompt reply, rly appreciate it. so origin would be (0,0) Second point would be (0,3) Third Point would be (5/root2, 3+(5/root2)) ? If that is the case, wouldn't the effort to find those co-ordinates already solve the length of the distance?

Homework Statement A car travels 3km due North then 5km North East. Use co-ordinate vectors to find the distance and direction from the starting point. Homework Equations I understand that co-ordinate vectors meant the column vector, but I don't understand how to convert the above...

so do i have to find t? how do i find t?

when r intersects the line?

im waiting online for help, so any help is much appreciated.. thanks in advance. =)

i tried to do that, but i have no idea how to find the position vector of q... some more hints pleasE? :p

do i find the length of AB first and work out the ratio?

Homework Statement Let A,B,C be the three points in R^3 with position vectors a=(1,-2,0) b=(-1,1,2) c=(7,1,6) respectively. Find the position vector q of the point Q that divides the line segment AB in the ratio 2:1, (where Q is closer to B.) Homework Equations The Attempt...

so its' -1,5,-1? thx chewy

so is the answer -1,5,-5? anyone?