b^2x^2+a^2y^2=a^2b^22xb^2+2ya^2 * y'=0b^2x^2+yy'a^2=0y'=-(b^2x^2)/(ya^2) y''=[-b^2*2x*ya^2+y'a^2 *b^2x^2]/(y^2a^4)y''=(-2b^2 *xy+y'b^2x^2)/(y^2a^2)y''=(-2xyb^2-b^2x^2/(ya^2)*b^2x^2)/(y^2a^2)y''=(-2xyb...