If a≠0 and the line 2bx+3cy+4d=0 passes through the points of intersection of the parabolas y2=4ax and x2=4ay, then
Given parabolas are y2=4ax .....(i)
x2=4ay .....(ii)
Putting the value of y from (ii) in (i), we get
x416a2=4ax⇒x(x3−64a3)=0⇒x=0,4a
from(ii), y=0, 4a. Let A ≡ (0,0); B ≡ (4a,4a)
Since, given line 2bx+3cy+4d=0 passes through A and B, ∴ d=0 and 8ab+12ac=0 ⇒ 2b+3c=0, (∴a≠0)
Obviously, a2+(2b+3c)2=0