## modphysnoob one year ago please look at my drawing @phi @KingGeorge

1. modphysnoob

|dw:1360298829035:dw| find this vector

2. itsmylife

your x axis coordinate is incorrect

3. itsmylife

it should be (4,0)

4. modphysnoob

yes , thanks

That is a beautiful triangle you have there.

6. itsmylife

then use mid point formula your gonna get, (2,1) as coordinates of bisector n then your vector is , V= 2i +j

7. KingGeorge

modphys doesn't want the mid point. He want the vector that's perpendicular.

8. itsmylife

well thats perpendicular bisector that means dividing equally that means mid point

9. KingGeorge

What I would do, is write the line in the form $$y=-x/2+2$$. The slope of the intersecting line will be $-\frac{1}{-\frac{1}{2}}=2.$ So you have a line that looks like $$y=2x$$ as the line that intersects. Set them equal to each other to get $$2x=-x/2+2\implies 5x/2=2\implies x=1$$.

10. KingGeorge

Plug that in again, $$x=1\implies y=2(1)=2$$, so the point of intersection is $$(1,2)$$.

11. KingGeorge

Which in turn means the vector is $\vec{i}+2\vec{j}$

12. modphysnoob

I got same answer but here what my book did

13. modphysnoob

14. KingGeorge

If $$x=.8$$, then the vector is $.8\vec{i}+1.4\vec{j}$ Taking the dot product of that with the vector $4\vec{i}-2\vec{j},$ we get $.8\cdot4-2\cdot1.4=0.4\neq0$so that solution is wrong.