The equation of the ellipse whose centre is at origin, major axis is along x-axis with eccentricity, and latus rectum 4 units is :
A cylindrical jar without a lid has to be constructed using a given surface area of a metal sheet. If the capacity of the jar is to be maximum, then the diameter of the jar must be k times the height of the jar. The value of k is
1
2
3
4
The following table gives the monthly expenditure of two families :
Expenditure in Rs | ||
Items | Family A | Family B |
Food | 3500 | 2700 |
Clothing | 500 | 800 |
Rent | 1500 | 1000 |
Education | 2000 | 1800 |
Miscellaneous | 2500 | 1800 |
In constructing a pie diagram to the above data, the radii of the circles are to be choosen by which one of the following ratios ?
1 : 1
10 : 9
100 : 91
5 : 4
If a circle of radius b units with centre at (0, b) touches the line y = x , then what is the value of b ?
Consider the two circles
What is the distance between the centres of the two circles ?
5 units
6 units
8 units
10 units
Consider the two circles
If circles intersect at two distinct. points, then which one of the following is correct ?
r = 1
r = 2
Consider a circle passing through the origin and the points (a, b) and (- b, - a). On which line does the centre of the circle lie ?
x + y = 0
x - y = 0
x + y = a + b
x - y = a2 - b2
Consider a circle passing through the origin and the points (a, b) and (- b, - a). What is the sum of the squares of the intercepts cut off by the circle on the axes ?
None of the above
B.
Equation of circle passing through origin :
x2 + y2 + 2gr + 2fy = 0
as, it is passes through (a, b) and (- b, - a), then
a2 + b2 + 2g.a + 2f.b = 0 ...(i)
and b2 + a2 - 2gb - 2fa = 0 ...(ii)
from (i) and (ii), we have,
(g + f)(a + b) = 0
g = - f
and on solving for g and f, we get