Let P(h,k) be a fixed point where h>0,k>0. A straight lien through P cuts the coordinate axes A and B. The minimum area of the triangle OAB is
Let the slope is m. then the equation of the line is y-k=m(x-h) It cuts the co ordinate axix at the points
A={(k-mh), 0} and B=0,(h−m/k) hence the area is Δ=1/2(k−mh)(h−m/k) then applying min condition for the variable m we get the min area is =2hk.