Question

HELP!!! How do you find the distance between 3x+4y+3=0 and (1,1)? Please Explain.

Answer 1

calc or geometry?

Answer 2

geometry, i guess...

Answer 3

haven't done calc yet

Answer 4

I recommend geometry, just not sure how it's called in english, but his name was Hess.

Answer 5

familiar with that concept?

Answer 6

\[\Large d(g,P)=\frac{3x+4y+3}{\sqrt{3^2+4^2}} \]

Answer 7

nope. sorry

Answer 8

I'm supposed to solve it using the equation Ay-Bx=C'

Answer 9

do you know what that means?

Answer 10

I don't understand the significance of the negative sign there, Ax+By=C' ? that would make more sense to me.

Answer 11

not sure. ill just use your equation. Thanks for the help anyway!!!

Answer 12

we can also try your way if you want, although I don't see the concept yet.

Answer 13

If you don't know about Hess' Normal Form you might want to use normal vectors instead, or haven't you done vectors yet?

Answer 14

yeah. i have done vectors

Answer 15

then you can easily find the normal vector to the given equation, it's given by the coefficients. Then you can define a new line going through the point (1,1) and cross it with the given line in the problem set to figure out the point perpendicular to the one on the line.

When you have two points you can apply the distance formula.

Answer 16

But this is a lot of work if you ask me hehe.

Answer 17

Haha..yeah. At least it actually makes sense to me.....

Thanks so much for your help!

Answer 18

welcome (-: