Find the equations of the straight lines drawn through the point $(1, - 2)$ $(1 ,-2)$ , making angle of $45°$ with the $x$ -axis?

Question

1435 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2018-06-13T16:41:49

The equations of the lines can be:

$y=x-3" " or" " y=-x-1$

A line which makes an angle of $45°$ with a horizontal line can have gradient of $1$ or $-1$

$m=1 and (1,-2)$ substituted into $y= mx+c$ gives:

$-2 = (1)(1) +c$
$-2 = 1+c$
$-3=c$

The equation is $y= x-3$

$m=-1 and (1,-2)$ substituted into $y= mx+c$ gives:

$-2 = (-1)(1) +c$
$-2 = -1+c$
$-1=c$

The equation is $y= -x-1$

Find the equations of the straight lines drawn through the point (1 ,-2)(1,−2)(1 ,-2), making angle of 45°45° with the xx-axis?