高中数学（数列）请找出下列数列的一个通项公式,使他的前四项分别是下了各数1）1,0,-1,02）-1+1/2,3-1/4,-5+1/8,7-1/16由於是当天作业实在是被逼无奈请各路高手帮帮忙!谢谢了
2019-05-27
高中数学（数列）
请找出下列数列的一个通项公式,使他的前四项分别是下了各数
1）1,0,-1,0
2）-1+1/2,3-1/4,-5+1/8,7-1/16
由於是当天作业实在是被逼无奈请各路高手帮帮忙!谢谢了
优质解答
1） sin(∏/2×n)
2)(-1)^n×(2n-1)-1/2^n×(-1)^n
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1） sin(∏/2×n)
2)(-1)^n×(2n-1)-1/2^n×(-1)^n
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