求证:无论x、y为何值,4x²-12x+9y²+30y+35的值恒为正.
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/15 03:29:07
![求证:无论x、y为何值,4x²-12x+9y²+30y+35的值恒为正.](/uploads/image/z/2519160-24-0.jpg?t=%E6%B1%82%E8%AF%81%EF%BC%9A%E6%97%A0%E8%AE%BAx%E3%80%81y%E4%B8%BA%E4%BD%95%E5%80%BC%2C4x%26%23178%3B-12x%2B9y%26%23178%3B%2B30y%2B35%E7%9A%84%E5%80%BC%E6%81%92%E4%B8%BA%E6%AD%A3.)
xN@_`0B篥Sms`ҪJ1bD+5Q|D$眹8Q5{=tv;t6ƝaHאE'T#W\YgOw[`9A,|ppwU-v;A09.8BpNަ87]Jf{KdRΥe"nqH1=8A&phyQ(9fƘؖ%#-bSʂE0gI$xbJ Op0]E=HjxnVY!2P"I5sZY`1|_iZ6f{|8\Ak$
求证:无论x、y为何值,4x²-12x+9y²+30y+35的值恒为正.
求证:无论x、y为何值,4x²-12x+9y²+30y+35的值恒为正.
求证:无论x、y为何值,4x²-12x+9y²+30y+35的值恒为正.
4x^2-12x+9+9y^2+30y+25+1=(2x-3)^2+(3y+5)^2+1
(2x-3)^2≥0,3y+5)^2≥0
(2x-3)^2+(3y+5)^2+1≥1
故恒大于0