Question

The equation to the tangent to the circle x² + y² = 4, which are parallel to x + 2y + 3 = 0 , are –

• A. x – 2y = 2
• B. x + 2y = ± 2$\sqrt { 3 }$
• C. x + 2y = ± 2 $\sqrt { 5 }$
• D. x – 2y = ± 2$\sqrt { 5 }$

Answer 1

Answer: (C)

x + 2y = ± 2 $\sqrt { 5 }$

Answer 2

let the tangents which are parallel to

x + 2y + 3 = 0 is x + 2y + l = 0 .....(i)

Now p = r ή $2 \sqrt { 5 }$

\ equation of tangent ήx+2y±$2 \sqrt { 5 }$= 0