Math Is Fun Forum
You are not logged in.
- Topics: Active | Unanswered
Pages: 1
#1 Re: Help Me ! » Quadrilateral midpoint vector proof » 2017-02-22 08:18:30
Thank You thickhead,
But for future reader a little correction, QH = (3a +2b + c + 2d)/ 4
#2 Re: Help Me ! » Inverse of function » 2017-02-22 01:04:18
Inverse of a function is the function which when combined to original function negates its operation.
f(x) o f(x)^-1 = f(x)^-1 o f(x) = identity operation (same as if no operation was performed) = x
#3 Re: Help Me ! » Quadrilateral midpoint vector proof » 2017-02-21 23:55:30
Three things I found out today,
1) I need to learn more.
2) You are Intelligent, your parallelogram trick was good.
3) You were born on a Monday
Thank You very much. 
But why MN is not relative to origin, ie why it is not (a+d)/2 + (a+b)/2, i know this is not correct but I am failing the intuition here.
#4 Re: Help Me ! » Geometry Proof. » 2017-02-21 21:30:54
hi Maroon900
Welcome to the forum.
At first I thought this was a use of the triangle inequality and, after a bit of manipulating, I got AD < AB + AC. Nearly there I thought. Then I tried a fresh approach:
Rotate the triangle about point D to create a new triangle A'BC below the first. The resulting shape ABA'C is a parallelogram (can you prove this?) and the diagonal is 2AD. You'll get the required result from this.
Bob
Brilliant. Creating parallelogram was the trick.
Maroon900, Hint, SSS and 2AD < AC+ A'C
#5 Re: Help Me ! » Quadrilateral midpoint vector proof » 2017-02-21 20:26:53
Already tried that, 
PM = QM - QP
QM = (a+d)/2
QP = - (c+d)/2
#6 Help Me ! » Quadrilateral midpoint vector proof » 2017-02-21 00:16:03
- Freiza
- Replies: 8
Prove that the line segments joining the midpoints of opposite sides of a quadrilateral bisect each other, using vectors.
I tried this,
but failed.
Pages: 1