](t,t3)=(3x2)x=t=3t2 So, equation tangent at P(t,t3) : y−t3=3t2(x−t) For point of intersection with y=x3 x3−t3=3t2x−3t3 ⇒(x−t)(x2+xt+t2)=3t2(x−t) For x≠t x2+xt+t2=3t2 ⇒x2+xt−2t2=0⇒(x−t)(x+2t)=0 So, for Q:x=−2t,Q(−2t,−8t3) ordinate of required point :