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Grade 12th passAnalytical Geometry

If two tangents to the parabola y^2=4ax from a point p makes angles theta 1 and theta 2 with the axis of the parabola ,then find the locus of p in each of the following cases. Theta1+theta2=alpha (constant ) and theta 1 + theta 2=π\2

Profile image of Jyoti
6 Years agoGrade 12th pass
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1 Answer

Profile image of Vikas TU
6 Years ago
Dear Jyoti 

tangent at parabola at (at12,2at1)  is yt1 =x+at12

so tangebt at (at22,2at2)  is yt2 =x+at22

these tangent meat at point P

so point p is

{at1t2,a(t1 +t2)}

 

 tan Θ1 =1/t1

 tanΘ 2 =1/t2

and tan(Θ1 + Θ2) = tan pi/2

simplify

so t1t2 =1

locus of point p

x=at1t2

x=a