It is known that ⊙ o is a circle with the origin as the center and √ 2 as the radius. The point P is a point on the straight line y = - x + 6. Through P, make a tangent PQ of ⊙ o, and Q is the tangent point. Then the minimum value of the tangent length PQ is

It is known that ⊙ o is a circle with the origin as the center and √ 2 as the radius. The point P is a point on the straight line y = - x + 6. Through P, make a tangent PQ of ⊙ o, and Q is the tangent point. Then the minimum value of the tangent length PQ is

Let P (m, 6-m), then OP ^ 2 = m ^ 2 + (6-m) ^ 2,
∴PQ^2=OP^2-OQ^2=2m^2-12m+34=2(m-3)^2+16.
When m = 3, the minimum PQ is 4