Question

The circle $${x^2} + {y^2} = 4x + 8y + 5$$     intersects the line $$3x-4y=m$$    at two distinct points if-

A. $$ - 35 < m < 15$$  
B. $$ 15 < m < 65$$
C. $$ 35 < m < 85$$
D. $$ - 85 < m < - 35$$
Answer :   $$ - 35 < m < 15$$
Solution :
Circle $${x^2} + {y^2} - 4x - 8y - 5 = 0$$
Centre $$ = \left( {2,\,4} \right),$$   Radius $$ = \sqrt {4 + 16 + 5} = 5$$
If circle is intersecting line $$3x-4y=m,$$    at two distinct points.
$$ \Rightarrow $$ length of perpendicular from centre to the line < radius
$$\eqalign{ & \Rightarrow \frac{{\left| {6 - 16 - m} \right|}}{5} < 5 \cr & \Rightarrow \left| {10 + m} \right| < 25 \cr & \Rightarrow - 25 < m + 10 < 25 \cr & \Rightarrow - 35 < m < 15 \cr} $$

Releted MCQ Question on
Geometry >> Circle

Releted Question 1

A square is inscribed in the circle $${x^2} + {y^2} - 2x + 4y + 3 = 0.$$      Its sides are parallel to the coordinate axes. The one vertex of the square is-

A. $$\left( {1 + \sqrt 2 ,\, - 2 } \right)$$
B. $$\left( {1 - \sqrt 2 ,\, - 2 } \right)$$
C. $$\left( {1 - 2 ,\, + \sqrt 2 } \right)$$
D. none of these
Releted Question 2

Two circles $${x^2} + {y^2} = 6$$    and $${x^2} + {y^2} - 6x + 8 = 0$$     are given. Then the equation of the circle through their points of intersection and the point $$\left( {1,\,1} \right)$$  is-

A. $${x^2} + {y^2} - 6x + 4 = 0$$
B. $${x^2} + {y^2} - 3x + 1 = 0$$
C. $${x^2} + {y^2} - 4y + 2 = 0$$
D. none of these
Releted Question 3

The centre of the circle passing through the point (0, 1) and touching the curve $$y = {x^2}$$   at $$\left( {2,\,4} \right)$$  is-

A. $$\left( {\frac{{ - 16}}{5},\,\frac{{27}}{{10}}} \right)$$
B. $$\left( {\frac{{ - 16}}{7},\,\frac{{53}}{{10}}} \right)$$
C. $$\left( {\frac{{ - 16}}{5},\,\frac{{53}}{{10}}} \right)$$
D. none of these
Releted Question 4

The equation of the circle passing through $$\left( {1,\,1} \right)$$  and the points of intersection of $${x^2} + {y^2} + 13x - 3y = 0$$      and $$2{x^2} + 2{y^2} + 4x - 7y - 25 = 0$$      is-

A. $$4{x^2} + 4{y^2} - 30x - 10y - 25 = 0$$
B. $$4{x^2} + 4{y^2} + 30x - 13y - 25 = 0$$
C. $$4{x^2} + 4{y^2} - 17x - 10y + 25 = 0$$
D. none of these

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Circle


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