UPSEE 2019 Solved Paper

Equation of tangent of parabola
y2=32x having slope m is y=mx+

8

m

.......(i)
Equation of tangent of parabola
x2=108y having slope m is y=mx−27m2 .......(ii)
Eqs. (i) and (ii) are identical
∴

8

m

=−27m2⇒m=−

2

3

Equation of common tangent of parabola is
y=

−2

3

x−12
⇒2x+3y+36=0
∴P(−18,0) and Q(0,−12)
PQ=√(18)2+(12)2 =√468=6√13