matlab已知式子求未知数'1=k/(1+a*exp^(b*6))','0.05=k/(1+a*exp^(b*1))','0.25=k/(1+a*exp^(b*3))'已知上面三个式子,如果求abk改怎么求.我用的[abk]=solve('1=k/(1+a*exp^(b*6))','0.05=k/(1+a*exp^(b*1))','0.25=k/(1+a*exp^(b*3))')

Question

matlab已知式子求未知数
'1=k/(1+a*exp^(b*6))',
'0.05=k/(1+a*exp^(b*1))',
'0.25=k/(1+a*exp^(b*3))'
已知上面三个式子,如果求a b k 改怎么求.
我用的[a b k]=solve('1=k/(1+a*exp^(b*6))','0.05=k/(1+a*exp^(b*1))','0.25=k/(1+a*exp^(b*3))')出来结果就是Warning:Warning,solutions may have been lost
Warning:Explicit solution could not be found.

Answer 1

表达式书写错误,如e^(b*6)应写为exp(b*6)才对.
>> eq1='1=k/(1+a*exp^(b*6))';
>> eq2='0.05=k/(1+a*exp(b*1))';
>> eq1='1=k/(1+a*exp(b*6))';
>> eq3='0.25=k/(1+a*exp(b*3))';
>> [a b k]=solve(eq1,eq2,eq3)
a =
60.270682493733339625877564168369
b =
-0.8931619555087691669792028421118
k =
1.2836183048834834881894212063089