5. Consider the ellipse (x^(2))/(16)+(y^(2))/(100)=1 .The tangent to this ellipse at (m, n) has x -intercept A=(a,0) and y- intercept B=(0,b) where a and b are positive. (a) Show that ab=(1600)/(mn) . (b) Use the relationship in part(a) and the fact that (m, n) lies on the ellipse to find the minimum value of ab .