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The equation of the common tangents to the circle`(x-3)^(2)+y^(2)=9` and the parabola `y^(2)=4ax` the x-axis, isA. `sqrt2y=3x+1`B. `sqrt3y=-(x+3)`C. `sqrt3y=x+3`D. `sqrt3y=-(3x+1)` |
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Answer» Correct Answer - C Let the common tangent to the parabola `y^(2)=4xbe,` `y=mx+1/m` It should be also touch the circle `(x-3)^(2)+y^(2)=9` Whose centre is (3,0) and radius =3, then `(|em+1//m|)/(sqrt(1+m^(2)))=3` `implies3m^(2)=1` `impliesm=pm(1)/(sqrt3)` But `m gt 0,` then equatio of common tangent is `y=(1)/(sqrt3)*x+sqrt3` `or sqrt3*y=x+3` |
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