Question

4分之1的n次方+负1的n次方-4分之负1的n次方+负1的n次方+1的值(n为正整数0

Answer 1

当n为奇数时,原式=（1/4）^n+(-1)^n-(-1/4)^n+(-1)^n+1

=(1/4）^n-1+(1/4)^n-1+1

=2(1/4）^n+(1/4)^n-1

当n为偶数时,原式=（1/4）^n+(-1)^n-(-1/4)^n+(-1)^n+1

=(1/4）^n+1-(1/4)^n+1+1

=3

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