忘记了密码?新用户?报名
现有的用户?登录
序列 { x n } \ {x_n \} {xn}满足关系 x 1 = 5 , x n + 1 = x n + 5 ( n = 1 , 2 , 3. , ... ) . c \开始{数组}{}&x_1 = 5,间{n + 1} = x_n + 5 & (n = 1, 2, 3, \ ldots)。结束\{数组} x1=5,xn+1=xn+5(n=1,2,3.,...).价值是什么 x 20. ? 间{20}? x20?
序列 { x n } \ {x_n \} {xn}满足关系 x 1 = 2 , x n + 1 = 2 x n + 1 ( n = 1 , 2 , 3. , ... ) . c \开始{数组}{}&x_1 = 2,间{n + 1} = 2 x_n + 1 & (n = 1, 2, 3, \ ldots)。结束\{数组} x1=2,xn+1=2xn+1(n=1,2,3.,...).价值是什么 x 5 ? 间{5}? x5?
序列 { x n } \ {x_n \} {xn}满足关系 x 1 = 1 , x 2 = 5 , x n + 2 = 4 x n + 1 + 5 x n ( n = 1 , 2 , 3. , ... ) . c \开始{数组}{}&x_1 = 1, &x_2 = 5,间{n + 2} = 4间{n + 1} + 5 x_n & (n = 1, 2, 3, \ ldots)。结束\{数组} x1=1,x2=5,xn+2=4xn+1+5xn(n=1,2,3.,...).价值是什么 x 8 625 ? \ dfrac {x_8} {625} ? 625x8?
序列 { x n } \ {x_n \} {xn}满足关系 x 1 = 1 , x 2 = 0 , 6 x n + 2 = 5 x n + 1 − x n ( n = 1 , 2 , 3. , ⋯ ) . c \开始{数组}{}&x_1 = 1, &x_2 = 0, &6x_ {n + 2} = 5间{n + 1} - x_n & (n = 1, 2, 3, \ cdots)。结束\{数组} x1=1,x2=0,6xn+2=5xn+1−xn(n=1,2,3.,⋯).价值是什么 n n n满足 x n = 1 3. 10 − 1 2 10 ? X_n = \dfrac{1}{3^{10}} - \dfrac{1}{2^{10}}? xn=3.101−2101?
序列 { x n } \ {x_n \} {xn}满足关系 x 1 = 4 , x n + 1 = x n + 3. n − 2 ( n = 1 , 2 , 3. , ... ) . c \开始{数组}{}&x_1 = 4,间{n + 1} = x_n + 3 n - 2 & (n = 1, 2, 3, \ ldots)。结束\{数组} x1=4,xn+1=xn+3.n−2(n=1,2,3.,...).价值是什么 x 12 ? 间{12}? x12?
问题加载…
注意加载…
设置加载…