设z为复数，i为虚数单位，若z2+1=0，则（z4+i）（z4-i）=______爱下问搜题

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问题填空题

设z为复数，i为虚数单位，若z²+1=0，则（z⁴+i）（z⁴-i）=______．

答案

因为z²+1=0，所以z²=-1，所以（z⁴+i）（z⁴-i）=（1+i）（1-i）=2

故答案为：2

补全对话，情景问答

从Ⅰ栏中找出与Ⅱ栏相匹配的答语。

Ⅱ
( )1. What's the weather like?
( )2. Is there a pay phone in the neighborhood?
( )3. Do you work in the hospital?
( )4. What's he doing?
( )5. Is the library between the hotel and mall?

Ⅰ
A. He is playing with his friends.
B. No, there isn't.
C. It is raining.
D. Yes, I do.
E. No, it isn't.

判断题

乘客电梯一般用于企业和宾馆饭店的服务部门。