Find all a for which the lines represented by the equations 2y+3+x=0 and 3y+ax+2=0 are perpendicular
Feb 26th 2007, 03:15 PM
topsquark
Quote:
Originally Posted by Rimas
Find all a for which the lines represented by the equations 2y+3+x=0 and 3y+ax+2=0 are perpendicular
Put the first line equation in slope-intercept form:
2y + 3 + x = 0
y = -(1/2)x - (3/2)
The second line needs to have a slope of +2 to be perpendicular to this line.
Thus:
3y + ax + 2 = 0
y = -(a/3)x - (2/3)
Thus -a/3 = 2. Thus a = -6.
-Dan
Feb 26th 2007, 03:22 PM
Plato
Quote:
Originally Posted by Rimas
Find all a for which the lines represented by the equations 2y+3+x=0 and 3y+ax+2=0 are perpendicular
If line l_1 has slope m_1 and line l_2 has slope m_2 then if neither line is vertical then the two line are perpendicular if (m_1)(m_2)=-1.
2y+3+x=0 has slope (-1/2); 3y+ax+2=0 has slope (-a/3).
Now solve for a.