已知数列{an}满足a1=1,a2=3,且an+2=(1+2|cosnπ2|)a
题型:解答题
问题:
已知数列{an}满足a1=1,a2=3,且an+2=(1+2|cos
(Ⅰ)求a3,a4; (Ⅱ)求a2k,a2k-1(k∈N+); (Ⅲ)设bk=a2k+(-1)k-1λ•2a2k-1(λ为非零整数),试确定λ的值,使得对任意(k∈N+)都有bk+1>bk成立. |
已知数列{an}满足a1=1,a2=3,且an+2=(1+2|cos
(Ⅰ)求a3,a4; (Ⅱ)求a2k,a2k-1(k∈N+); (Ⅲ)设bk=a2k+(-1)k-1λ•2a2k-1(λ为非零整数),试确定λ的值,使得对任意(k∈N+)都有bk+1>bk成立. |