- #1

- 18

- 0

**Please Help With A Proof!!**

If L1 is perpendicular to L2, prove that the slope of L2 is the negative reciprocal of the slope of L1..

PLEASE HELP ME!!

You are using an out of date browser. It may not display this or other websites correctly.

You should upgrade or use an alternative browser.

You should upgrade or use an alternative browser.

- Thread starter STAR3URY
- Start date

- #1

- 18

- 0

If L1 is perpendicular to L2, prove that the slope of L2 is the negative reciprocal of the slope of L1..

PLEASE HELP ME!!

- #2

EnumaElish

Science Advisor

Homework Helper

- 2,322

- 124

What is the definition of perpendicular? definition of slope? Any ideas?

- #3

- 18

- 0

What is the definition of perpendicular? definition of slope? Any ideas?

Perpendicular is when two lines intersect to form 90 degree angles, slope is whether the line is moving up or down, and how much like the top value is the y and the bottom is the x.

- #4

rock.freak667

Homework Helper

- 6,223

- 31

- #5

Dick

Science Advisor

Homework Helper

- 26,263

- 619

- #6

- 18

- 0

- #7

Dick

Science Advisor

Homework Helper

- 26,263

- 619

If you can't rotate a point 90 degrees, then what's your definition of perpendicular?

- #8

- 18

- 0

If you can't rotate a point 90 degrees, then what's your definition of perpendicular?

During class all he told us was to prove that if

1). L1 is perpendicular to L2

2). slope of L1 is M1 where M1 can't be 0

prove that slope of L2 is -1/M1...thats it and he said not to use anything we didn't learn, he didnt talk about rotating anything, or trignometry. =(

- #9

Dick

Science Advisor

Homework Helper

- 26,263

- 619

- #10

- 18

- 0

- #11

Dick

Science Advisor

Homework Helper

- 26,263

- 619

Oh, come on. You said the definition of perpendicular is that the lines meet at 90 degree angles. This means you can use some geometry. Use it.

- #12

EnumaElish

Science Advisor

Homework Helper

- 2,322

- 124

Did you learn to define perpendicular in terms of inner products (of two vectors)?

- #13

HallsofIvy

Science Advisor

Homework Helper

- 41,847

- 966

That makes no sense. Apparently you want to PROVE that his definition is... what? Equivalent to some other definition, apparently! You can't PROVE that his definition is correct using only his definition! What is YOUR definition of perpendicular? That two lines intersect at 90 degrees?

- #14

- 2

- 0

so slope 1 = -1/slope 2

- #15

EnumaElish

Science Advisor

Homework Helper

- 2,322

- 124

One man's definition can be another's problem.

so slope 1 = -1/slope 2

- #16

- 2

- 0

What is the lesson you took ? to determine the proof ?

Share: