如何证a^2/x+b^2/y>=(a+b)^2/(x+y)..a b为正常数,且a不等于b

如何证a^2/x+b^2/y>=(a+b)^2/(x+y)..a b为正常数,且a不等于b (2x+3y)(a-b)-2(a-b)(x+y)如何化简 (2x 3y)(a-b)-2(a-b)(x y)如何化简 化简?(x+y)(a+b)-(x-y)(2a+b) 不全部拆开如何化简? [a'(x)b(x)-a(x)b'(x)]/b(x)^2​//如何通分得到的?y(x)=a(x)/b(x)分子求导a'x/b(x),对分母求导是-a(x)b'x/b(x)^2两者通分相加[a'(x)b(x)-a(x)b'(x)]/b(x)^2 (a-b)(x-y)-(b-a)(x y)如何解题 (x+y)(a-2b) 填空：(b-a)(2x-y+1)=(a-b)( ) 已知a,b,X,Y属于R+,求证a^2/X+b^2/Y>=(a+b)^2/(X+Y) (a-b)x+(a+b)y=2(a²-b²) (a+b)x+(a-b)y=2(a²+b²) 解方程组 (a-b)x+(a+b)y=2(a²-b²) (a+b)x+(a-b)y=2(a²+b²) 解方程组 已知：A=X*X-3xy+y*y,B=2x*x+xy-3y*3y.求A+B,A-B,A+2B 已知实数a,b,x,y,满足不等式（a+b）(x+y)>2(ay+bx),求证（x-y）/(a-b)+(a-b)/(x-y)>=2 抛物线y=2-(x-a)(x-b)(a 如何计算(a+b)(x+y) 如何通分x/a,y/b? 通分 a/(y-x)^2,b/(x-y)(x+y) 因式分解a(x-y)+b(y-x)+(2x-y)