dtweah wrote:The distance between the point (1,2) and a line in the X-Y plane is (3(2)^0.5)/4. If the y intercept of the line is 5/2 find the slope of the line?
A. -1
B -1/2
C. 1/2
D. 1
E. 2
Altough you could use the distance to a line formula and solve you can also solve without it. Put eqn into y=mx+b y=mx+5/2 or 2y=mx+5. Plug point in (1,2) you can find slope m.
2(2)=m(1)+5
m=1
Choose D.
Using Distance Formula:
Rationalize distance. 3/(2)2^.5
Denominator equal square root of 8=4+4 or 2^2+2^2
So A=+-2 and B=+-2
|Ax +B +C|=|3| From y intercept info you know C=5 and A =2
|2(1)+B(2)+5|=3
|7+2B|=3
The def of absolute value has:
7+2B= 3, for B=-2, this solves.
7+2B=-3, since distance is never negative we ignore this part
The eqn is 2x-2y=5 from which the slope can be determined to be 1.
Choose D.
The first method solved under 1 min. The second about midway over 1.