Circle And System Of Circles Question 360
Question: Square of the length of the tangent drawn from the point $ (\alpha ,\beta ) $ to the circle $ ax^{2}+ay^{2}=r^{2} $ is
Options:
A) $ a{{\alpha }^{2}}+a{{\beta }^{2}}-r^{2} $
B) $ {{\alpha }^{2}}+{{\beta }^{2}}-\frac{r^{2}}{a} $
C) $ {{\alpha }^{2}}+{{\beta }^{2}}+\frac{r^{2}}{a} $
D) $ {{\alpha }^{2}}+{{\beta }^{2}}-r^{2} $
Show Answer
Answer:
Correct Answer: B
Solution:
Length of tangent is $ \sqrt{S_1} $ . Equation of circle is $ x^{2}+y^{2}-\frac{r^{2}}{a}=0 $
Hence $ S_1={{\alpha }^{2}}+{{\beta }^{2}}-\frac{r^{2}}{a} $ .
BETA
