Steve Jobs' well-known sayings, for example, “Stay hungry, stay foolish”, as well as all his great ____ (achieve) in technology will light up the way to the future for the young.

下列气体不会造成大气污染的是(　　)

已知如图，直线AB、CD相交于点O，∠COE=90°．

用简便方法计算。

已知a₁=3，a_n=2a_n﹣1+（t+1）•2ⁿ+3m+t（t，m∈R，n≥2，n∈N^*）