xem ai thông minh hơn nào

T

thutuanprocute

Cau1
Để x/(x+10)^2 dat gia tri Max khi va chi khi (x+10)^2/x dat gia tri Min
Ta co(x+10)^2/x=(x^2+20x+100)/x=x+100/x+20>=20+20=40
Suy ra max x/(x+10)^2=1/40 khi va chi khi x=100/x suy ra x=10
Cau 2.
Cau tu chung minh,,roi ap dung:
3(x^2+y^2+z^2)>=(x+y+z)^2
Dau dang thuc xay ra khi va chi khi x=y=z
nho phai cam on do nghe ,bai kho cu alo cho thutuanprocute la xo ngay

:khi (84)::khi (190)::khi (189):
 
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