求证:无论x,y为何值,4x²-12x+9y²+30y+35的值求证: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:2024/05/09 13:05:30
求证:无论x,y为何值,4x²-12x+9y²+30y+35的值求证: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
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的值求证:无论x,y为何值,4x²-12x+9y²+30y+35的值恒为正
4x²-12x+9y²+30y+35
=(4x²-12x+9)+(9y²+30y+25)+1
=(2x-3)²+(3y+5)²+1
∵(2x-3)²+(3y+5)≥0
∴4x²-12x+9y²+30y+35=(2x-3)²+(3y+5)²+1>0
即:无论x,y为何值,4x²-12x+9y²+30y+35的值恒为正

4x^2-12x+9y^2+30y+35
=4x^2-12x+9+9y^2+30y+25+1
=(2x-3)^2+(3y+5)^2+1>0

4x²-12x+9y²+30y+35
=4(x²-3x)+9(y²+10y/3)+35
=4(x²-3x+9/4) + 9(y²+10y/3+25/9) + 1
=4(x - 3/2)² + 9(y + 5/3)² + 1
=(2x - 3)² + (3y + 5)² + 1 ≥ 1 > 0

4x²-12x+9y²+30y+35
=4x²-12x+9+9y²+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>0
无论x,y为何值,4x²-12x+9y²+30y+35的值恒为正。
请采纳,加油!