Consider the parabola x^2+4y=0.let P=(a,b) be any fixed point inside the parabola and let S be the focus of the parabola then the minimum value at SQ+PQ as point Q moves on the parabola is

Dear Student,
The minimum value of SQ is attained when Q reaches a point where it is perpendicular to S (the focus). There, SQ will be half the length of the latus rectum.
 Half the length of latus rectum = |4a|/2 = 2 units
 Therefore, minimum SQ = 2 units

Since, P can be any point inside the parabola, the length PQ cannot be determined precisely. 
However, for PQ + SQ to me minimum, P should lie on the latus rectum as close to Q as possible so that PQ + SQ is minutely greater than 2 units.

Regards
​​
​​​​