\((\)Ⅰ\()\)求直线\(AC\)与\(PB\)所成角的余弦值;
\((\)Ⅱ\()\)在侧面\(PAB\)内找一点\(N\),使\(NE\bot \)面\(PAC\),并求出点\(N\)到\(AB\)和\(AP\)的距离.
进入组卷