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高考总复习优化设计二轮用书数学A配基础版考前强化练
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这是一份高考总复习优化设计二轮用书数学A配基础版考前强化练,文件包含限时练6pptx、限时练5pptx、限时练1pptx、限时练4pptx、限时练2pptx、限时练3pptx、2复数平面向量pptx、3排列组合与二项式定理pptx、1集合常用逻辑用语不等式pptx、规范练3pptx、规范练1pptx、抢分练2pptx、规范练2pptx、规范练6pptx、抢分练1pptx、规范练4pptx、规范练5pptx等17份试卷配套教学资源,其中试卷共0页, 欢迎下载使用。
1.(13分)(2024·江苏连云港模拟)已知函数f(x)=(1)求函数f(x)在x=1处的切线方程;(2)证明:∀x∈[0,+∞),f(x)>sin x.
令h(x)=ex-x-1,可得h'(x)=ex-1.当x∈[0,+∞)时,h'(x)=ex-1≥0,所以h(x)=ex-x-1在区间[0,+∞)上单调递增,所以h(x)≥h(0)=e0-0-1=0,即f'(x)=ex-x-1≥0,
当x=0时,f(0)=1>sin 0=0,当x>0时,f(x)>1≥sin x.综上所述,∀x∈[0,+∞),f(x)>sin x.
(2)sin C(1+cs B)=sin B(2-cs C),(方法一)sin C+sin Ccs B+sin Bcs C=2sin B,∴sin C+sin(B+C)=2sin B,∴sin C+sin A=2sin B,根据正弦定理得c+a=2b.由余弦定理得a2=b2+c2-2bccs A=b2+c2+bc,①将a=2b-c代入①式,得3b2-5bc=0,
3.(15分)(2024·山东泰安模拟)如图1,在直角梯形ABCD中,AD∥BC, ∠BAD= ,AB=BC= AD,E是AD的中点,O是AC与BE的交点.将△ABE沿BE折起到△A1BE的位置,如图2.
(1)证明:平面BCDE⊥平面A1OC;(2)若平面A1BE⊥平面BCDE,求平面A1BC与平面A1CD夹角的余弦值.
所以四边形ABCE为正方形,四边形BCDE为平行四边形,所以BE⊥AC,CD∥BE.
即在图2中,BE⊥OA1,BE⊥OC,OA1∩OC=O,OA1,OC⊂平面A1OC,所以BE⊥平面A1OC.又因为BE⊂平面BCDE,所以平面BCDE⊥平面A1OC.
(2)解 因为平面A1BE⊥平面BCDE,平面A1BE∩平面BCDE=BE,A1O⊥BE,A1O⊂平面A1BE,所以A1O⊥平面BCDE.又因为OC⊂平面BCDE,所以A1O⊥OC.又由(1)知BE⊥OC,BE⊥OA1,所以直线BE,OC,OA1两两垂直.如图,以O为坐标原点,分别以OB,OC,OA1所在直线为x轴、y轴、z轴建立如图所示的空间直角坐标系,设A1B=1,所以A1B=A1E=BC=ED=1.
设平面A1BC的法向量n1=(x1,y1,z1),平面A1CD的法向量n2=(x2,y2,z2),平面A1BC与平面A1CD夹角为θ,
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