已知ax+by=7ax^2+by^2=49ax^3+by^3=133ax^4+by^4=406试求1995(x+y)+6xy-17/2(a+b)的值过程要详细已知ax+by=7,ax^2+by^2=49,ax^3+by^3=133,ax^4+by^4=406 试求1995(x+y)+6xy-17/2(a+b)的值
来源:学生作业帮助网 编辑:作业帮 时间:2024/05/15 11:45:05
已知ax+by=7ax^2+by^2=49ax^3+by^3=133ax^4+by^4=406试求1995(x+y)+6xy-17/2(a+b)的值过程要详细已知ax+by=7,ax^2+by^2=49,ax^3+by^3=133,ax^4+by^4=406 试求1995(x+y)+6xy-17/2(a+b)的值
已知ax+by=7ax^2+by^2=49ax^3+by^3=133ax^4+by^4=406试求1995(x+y)+6xy-17/2(a+b)的值过程要详细
已知ax+by=7,ax^2+by^2=49,ax^3+by^3=133,ax^4+by^4=406 试求1995(x+y)+6xy-17/2(a+b)的值
已知ax+by=7ax^2+by^2=49ax^3+by^3=133ax^4+by^4=406试求1995(x+y)+6xy-17/2(a+b)的值过程要详细已知ax+by=7,ax^2+by^2=49,ax^3+by^3=133,ax^4+by^4=406 试求1995(x+y)+6xy-17/2(a+b)的值
tt=pt+q
(x,y)是两根
F(n)=ax^n+by^n
F(n+2)=pF(n+1)+qF(n)
133=49p+7q
406=133p+49q
p=2.5
q=1.5
所以
2F(n+2)=5F(n+1)+3F(n)
2tt-5t-3=0
(2t+1)(t-3)=0
x+y=5/2
xy=-3/2
x=3
y=-1/2
3a-1/2b=7,9a+b/4=49
a=5,b=16
所以a=5,b=16,x=3,y=-1/2
你自己回代吧!
tt=pt+q
(x,y)是两根
F(n)=ax^n+by^n
F(n+2)=pF(n+1)+qF(n)
133=49p+7q
406=133p+49q
p=2.5
q=1.5
所以
2F(n+2)=5F(n+1