2022高一英语周报第50期答案

I was already at the mall door when Mathew caught upwith me. " Do you have 750 plus 25 for delivery, ma'am?Yes. Yes. That's about all I have, "Well then, you just have your husband sitting at the front gate on Fridaymorning around 10 o'clock so he can be there when my Dad and I come to unload his new canoe.(高分句型)We'll even put a bow on it for his birthday "I started to cry. My old hand shook as I wrote out my cheque(马修追上我商量独木舟的事)Ma'am. There's something you should know. This store was my Grandpa's and the canoe had been orderedby him. He always promised to retire one day. Said hewanted to spend time relaxing and out fishing in a canoe. "He swallowed hard. "My Grandpa died, sudden-likejust last week. He was only 68 years old. I think he'd bemighty happy that your husband will get this canoe高分句型二) You just have to make sure he uses it a lot, okay? Promise""I promise, " I said as I dashed off toook for my dear sweet husband.(马修以一个十分便宜的价格卖给了我,只要我答应好好对待这个独木舟

1.【必备知识】本題考查的知识是“了解函数的单调性与导数的关系;能利用导救研究函数的单调性,会求函数的单调区间(其中多项式函数不超过三次)”【关键能力】本題考查运算求解能力、逻輯思维能力【学科素养】试題综合考查一次函数、对数函数,考查函数的单调性及零点,很好地体现了数学探索、理性思维等学科素养【解题思路】(1)f(x)-f'(x)一→分a≤0,a≥1,0 0)h(x)=2ax(x>0-osoh'(x)>0一h(x)在0,+∞)上单调递增→不满足题意函数h(x)的单调性→函数h(x)的最大值为hh(x)有两个不同的零点经验证0 0)(7分)当a≤0时,h'(x)>0,函数h(x)在(0,+∞)上单调递增,h(x)至多有个零点,不满足题意(8分)当>0时,令(x)=0.解得x=2,则函数h()在0.2)上单调递增,在(一,+∞)上单调递减,所以h(x)m,=h(-)=hn(9分)因为函数h(x)有两个不同的零点,所以h(÷)=hn->0,即>1,得0 1>M()=-20设g(x)=e-x2-1(x>0),则g'(x)=e-2x,令φ(x)=e-2x(x>0),则q'(x)=e-2,令φ'(x)=0,得x=lhn2,所以当0 ln2时,φ'(x)>0,φ(x)单调递增,所以p(x)≥(hn2)=e"2-2h2=2-2hn2>0,所以g(x)在(0,+∞)上单调递增,所以g(x)>0,即e'>x2+1(x>0).设t(x)=e-x(x>1),则t'(x)=e“-1>0,所以t(x)在(1,+∞)上单调递增,所以t(x)>0,即e'>x(x>1)2又二>1,所以则h(e")121<2+a+1)2+1a<0,(11分)因此,实数a的取值范围为(0,2)(12分)解法二由题意得函数h(x)=1ox+In x(x>0)则函数h(x)=1-2-2恰有两个不同的零点即方程1-2x+lhx=0恰有两个不同的根(7分)由1-x+lnx=0得a=2(1+lnx)所以直线y=a与函数8(x)=2(1+1mx的图象有两个不同的交点(9分)由g(x)2(1+lnx),得g'(x)当0 0,g(x)单调递增,当x>1时,g'(x)<0,g(x)单调递减所以g(x)m=g(1)=2.(11分)又e 0,所以实数a的取值范围为(0,2)(12分)

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