已知<img alt="" height="24" src="/api/uploads/1537916/in-rich-contentcreated_at=1647290540" width="91">,则<img alt="" height="21" src="/api/uploads/1537917/in-rich-contentcreated_at=1647290540" width="61">1 。(填空题)

出自:2024年国家开放大学答案