Question

MEDAL!!!



Is it possible for two lines with positive slopes to be perpendicular to each other?

Answer 1

I think I got it. The slope needs to be negative reciprocals of the other. So like 5x needs to be -1/5x?

Answer 2

Am I correct?

Answer 3

@Michele_Laino

Answer 4

No. Theres no way for a line to cross another and form right angles unless one has a negative slope and one has a positive slope.
"If two lines are perpendicular and neither one is vertical, then one of the lines has a positive slope, and the other has a negative slope. Also, the absolute values of their slopes are reciprocals."
http://www.cliffsnotes.com/math/geometry/coordinate-geometry/slopes-parallel-and-perpendicular-lines

Answer 5

if two perpendicular lines have their slopes , say m_1, and m_2 both positive, then the product of such slopes is also positive, namely:
\[\large {m_1}{m_2} > 0\]

Answer 6

it is a contradiction, since we know that the product of such slopes has to check this condition:
\[\large {m_1}{m_2} = - 1\]

Answer 7

So I need to make a perpendicular line through the -2,3 point.
How can I do that?

Answer 8

it is simple the slope of the requested line, is:
\[\large m = - \frac{1}{5}\]

Answer 9

I have the slope intercept form for -2,3 as y=5x + 2

Answer 10

so you have to apply this equation:
\[\large y - 3 = - \frac{1}{5}\left( {x + 2} \right)\]

Answer 11

So now do I need to do: -1/5x + 2= y?

Answer 12

Is your and my equations the same thing? @Michele_Laino

Answer 13

I think that they are different equations, since after a simplification, I can rewrite my equation as follows:
\[\large y = - \frac{x}{5} + \frac{{13}}{5}\]

Answer 14

Would that line work?

Answer 15

My line doesn't work. It is not perpendicular.

Answer 16

I think not, since that line is not perpendicular to both the parallel lines

Answer 17

please try with this line:
\[\large y = - \frac{x}{5} + \frac{{13}}{5}\]

Answer 18

@Michele_Laino How did you get 13/5?

Answer 19

here are the missing steps:
\[\large \begin{gathered}
y - 3 = - \frac{x}{5} - \frac{2}{5} \hfill \\
\hfill \\
y = - \frac{x}{5} - \frac{2}{5} + 3 \hfill \\
\hfill \\
y = - \frac{x}{5} + \frac{{15 - 2}}{5} \hfill \\
\hfill \\
y = - \frac{x}{5} + \frac{{13}}{5} \hfill \\
\end{gathered} \]

Answer 20

I still do not get how you got 13/5.

These are my steps:
\[y - 3 = -\frac{ 1 }{ 5 } (x+2)\]
\[y - 3=-\frac{ 1 }{ 5 }x-\frac{ 2 }{ 5 }\]
\[y=-\frac{ 1 }{ 5 }x-\frac{ 2 }{ 5 } + 3\]
\[y=-\frac{ 1 }{ 5 }x+\frac{ 3 }{ 5 }\]

Answer 21

I am really sorry fir being redundant. :(

Answer 22

*for

Answer 23

hint:
\[ \Large - \frac{2}{5} + 3 = \frac{{ - 2 + \left( {3 \times 5} \right)}}{5} = ...?\]

Answer 24

How did you get -2+(3 x 5)?

Answer 25

since the least common multiple of 5 and 1 is 5
\[\Large - \frac{2}{5} + 3 = - \frac{2}{5} + \frac{3}{1}\]

Answer 26

and multipling both numerator and denominator of the second fraction, by 5, we get:
\[\large \frac{2}{5} + \frac{3}{1} = - \frac{2}{5} + \frac{{3 \times 5}}{{1 \times 5}} = - \frac{2}{5} + \frac{{15}}{5} = \frac{{ - 2 + 15}}{5}\]

Answer 27

Oh okay!!!!! I totally get it now :)

Answer 28

:)

Answer 29

So for x I can input any number now?