- Home
- Standard 11
- Mathematics
10-1.Circle and System of Circles
normal
If the line $y = mx + c$be a tangent to the circle ${x^2} + {y^2} = {a^2}$, then the point of contact is
A
$\left( {\frac{{ - {a^2}}}{c},{a^2}} \right)$
B
$\left( {\frac{{{a^2}}}{c},\frac{{ - {a^2}m}}{c}} \right)$
C
$\left( {\frac{{ - {a^2}m}}{c},\frac{{{a^2}}}{c}} \right)$
D
$\left( {\frac{{ - {a^2}c}}{m},\frac{{{a^2}}}{m}} \right)$
Solution
(c) Find points of intersection by simultaneously solving for $x$ and $y$ from $y = mx + c$ and ${x^2} + {y^2} = {a^2}$ which comes out as
$\left( { – \frac{{{a^2}m}}{c},\;\frac{{{a^2}}}{c}} \right)$.
Standard 11
Mathematics
