如果a^2+b^2/2ab=2,求代数式7ab/(a^2+b^2)+(3a^2+5ab+3b^2)/6ab的值

来源:学生作业帮助网 编辑:作业帮 时间:2024/11/07 23:55:48

如果a^2+b^2/2ab=2,求代数式7ab/(a^2+b^2)+(3a^2+5ab+3b^2)/6ab的值
如果a^2+b^2/2ab=2,求代数式7ab/(a^2+b^2)+(3a^2+5ab+3b^2)/6ab的值

如果a^2+b^2/2ab=2,求代数式7ab/(a^2+b^2)+(3a^2+5ab+3b^2)/6ab的值
(a^2+b^2)/2ab = 2
a^2+b^2 = 42ab
7ab/(a^2+b^2)+(3a^2+5ab+3b^2)/6ab
=7ab/(a^2+b^2) + [3(a^2+b^2)+5ab]/6ab
=7ab/(4ab)+(12ab+5ab)/(6ab)
=7/4 +17/6
=55/12

由a^2+b^2/2ab=2得a^2+b^2=4ab
7ab/(a^2+b^2)+(3a^2+5ab+3b^2)/6ab=7ab/4ab+(12ab+5ab)/6ab
=7/4+17/6=55/12

题目是这样的吧(a²+b²)/2ab=2
那么a²+b²=4ab
所以7ab/(a²+b²)+(3a²+5ab+3b²)/6ab=7/4+(12ab+5ab)/6ab=7/4+17/6=55/12

a^2+b^2/2ab=2
则a^2+b^2=4ab
所以ab/(a^2+b^2)=1/4
(3a^2+5ab+3b^2)/6ab
=(4ab+5ab)/6ab
=9ab/6ab
=3/2
所以原式=7/4+3/2=13/4