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1年前
As the income is increasing,the________of family life has been changing over recent years. [ ]
1年前
给下列问句选择正确的答语。What animal can run very fast?
1年前
已知{an}是等比数列,a1=3,a4=24,数列{bn}满足:b1=0,bn+b(n+1)=an, (1)求证an=3×2^n-1; (2)求证:bn=2^(n-1)+(-1)^n.
1年前
二次函数y=-2x^2的图象经两次平移后得到抛物线y=-2x^2+bx+c,且经过(1,2),(-1,0)两点,试说出平移的过程.
1年前