K=0, parallel to the Y axis, and the straight line intersects the ellipse in the first and second quadrants. Simultaneous straight lines and elliptic equations find the absolute value of the abscissa of the intersection point, which is half of the base of the triangle. After taking twice, 2*X*b*0.5 is the triangle area. According to the basic inequality or inequality solution, find the maximum value and set the coordinate A(X 1, X2)B(X3, X4).