NIMCET 2007 — Mathematics PYQ
NIMCET | Mathematics | 2007The distance between the pair of straight lines x2+23xy+2y2+4x+1=0 is:
Choose the correct answer:
- A.
23
- B.
2
- C.
3
3
Explanation
Given equation:
x2+23xy+2y2+4x+1=0
Comparing with ax2+2hxy+by2+2gx+2fy+c=0:
a=1
h=3
b=2
g=2
f=0
c=1
Check condition for parallel lines:
h2=(3)2=3
ab=1×2=2
Since h2=ab, the lines are not parallel.
Check for standard typo (b=3 instead of 2):
If the equation is x2+23xy+3y2+4x+1=0:
a=1,b=3,g=2,c=1
Formula for distance between parallel lines:
d=2a(a+b)g2−ac
d=21(1+3)22−1(1)
d=244−1=2×23=3
Correct Answer:
(d) none (or (c) 3
Explanation
Given equation:
x2+23xy+2y2+4x+1=0
Comparing with ax2+2hxy+by2+2gx+2fy+c=0:
a=1
h=3
b=2
g=2
f=0
c=1
Check condition for parallel lines:
h2=(3)2=3
ab=1×2=2
Since h2=ab, the lines are not parallel.
Check for standard typo (b=3 instead of 2):
If the equation is x2+23xy+3y2+4x+1=0:
a=1,b=3,g=2,c=1
Formula for distance between parallel lines:
d=2a(a+b)g2−ac
d=21(1+3)22−1(1)
d=244−1=2×23=3
Correct Answer:
(d) none (or (c) 3

