共50条信息
已知三棱柱\(.ABC-A_{1}B_{1}C_{1}\)的侧棱与底面垂直,底面是边长为\(\sqrt{3}\)的正三角形\(.\)若\(P\)为底面\(A_{1}B_{1}C_{1}\)的中心,\(PA\)与平面\(ABC\)所成角的大小为\(\dfrac{\pi }{3}\),则棱柱\(ABC-A_{1}B_{1}C_{1}\)的体积为( )
如图,在长方体\(ABCD\)\(-\)\(A\)\({\,\!}_{1}\)\(B\)\({\,\!}_{1}\)\(C\)\({\,\!}_{1}\)\(D\)\({\,\!}_{1}\)中,\(AB\)\(=\)\(BC\)\(=2\),\(AA\)\({\,\!}_{1}=1\),则\(BC\)\({\,\!}_{1}\)与平面\(BB\)\({\,\!}_{1}\)\(D\)\({\,\!}_{1}\)\(D\)所成角的正弦值为\((\) \()\)
直三棱柱\((\)侧棱垂直于底面的三棱柱\()ABC—A_{1}B_{1}C_{1}\)中,底面是正三角形,三棱柱的高为\(\sqrt{3}\),若\(P\)是\(\triangle A_{1}B_{1}C_{1}\)的中心,且三棱柱的体积为\(\dfrac{9}{4}\),则\(PA\)与平面\(ABC\)所成角的大小是
正方体\(ABCD-A_{1}B_{1}C_{1}D_{1}\)中,\(BB_{1}\)与平面\(ACD_{1}\)所成角的余弦值为\((\) \()\)
直线\(a\)与平面\(α\)所成的角为\(50^{\circ}\),直线\(b/\!/a\),则直线\(b\)与平面\(α\)所成的角等于( )
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