八年级英语周报2022–2022学年答案

12.ABD【试题情境】本題是综合性题目,属于探索创新情境,具体是数学探究情境【关键能力】本题考查运算求解能力,逻辑思维能力【解题思路】取x=y=0,易得f(0)=1;取x=y=,可得∫(x)=(2+2)=[(2)]3≥0,然后验证f(x)=0的情况;由当x>0时,f(x)>1,且f(0)=1可得,当x>0时,f(x)>f(0),与f(x)为减函数矛盾,从而可判断C错误;先证明f(x)的单调性,然后由f(2)=2可得f(1)=4,结合函数的单调性可得出y-nx-≤1,再化简、换元,通过构造函数、求导得新函数的单调性和最值,即可得解【解析】取x=y=0,则f(0)=[f(0)]2,解得f(0)=0或f(0)=1,若f(0)=0,则对任意的x>0,f(x)=f(x+0)=f(x)f(0)=0,与条件不符,故f(0)=1,A正确;对任意的xER,(x)=f(2+2)=(2)]=0,若存在x∈R,使得f(x0)=0,则f(0)=f(x+(-x))=f(x0)f(-x0)=0,与f(0)=1矛盾,所以对任意的x∈R,f(x)>0,B正确;当x>0时,f(x)>1,且f(0)=1,所以当x>0时,f(x)>f(0),与f(x)为减函数矛盾,C错误;假设x1>x2,则∫(x1)-f(x2)=f(x1-x2+x2)-f(x2)=f(x1x2)f(x2)-f(x2)=[f(x1-x2)-1f(x),因为x1-x2>0,所以f(xx2)>1,则f(x1)-f(x2)>0,即f(x1)>f(x2),所以函数f(x)在R上单调递增,由题意得f(1)=f()12=4,所以(出xx)≤f(1),结合∫(x)在R上单调递增可知xx-≤1,则令t=—,则t>0,-a≤tlnt+t,令F(x)=xnx,则F"(x)=hnx+2,易得F(x)在(0,)上单调递减,在(一,+)上单调递增,从而F(x)≥F(e2)=-与,所以-a≤-,则D正确.团解题关键》求解本题D选项的关键是求出函数f(x)的单调性,进而将∫(yx-)≤4转化为y-x-≤1求解

读后续写Possible version lI stared at the paper and then looked around. I was cold. Although I could not see my sistersnor the new house, which was hidden from my sight by a grey wall, I got the feeling that I was notalone. Walking along the shore was a tall familiar figure who looked lost in his thoughts. I lookedgain at the paper in my hand, closed my eyes and wishedAs /opened my eyes, I found my father was standing right beside me. Happy birthday, sonhe said, patting my shoulder gently. I smiled up at him and took his hand. Looking back, life fromthat day on marked the start of a close bond and a strong friendship with my father. What was mybirthday surprise? Wishes do come truePossible version 2I stared at the paper and then looked around. On the backside, there was a map. I noticed thatit was clearly leading me in a direction, but who could have sent this? I stood there in silence andstudied it. I decided to follow the map and it led me down the beach until I reached a staircase. Iooked back and could no longer see my siblings. I continued to follow the point on the map, untilI unexpectedly lost my footing and fell zksq down the stepsAs I opened my eyes, I found my father was standing right beside me. Happy birthday, sonhe said, patting my shoulder gently. Then he asked how I had come upon this place? I explained tohim that I had found the bottle in the ocean and when I opened it had the words on it. Shocked bythe message, my father realized what I had found I threw this bottle into the ocean many years agowhen I was alone. he said. I used to come to this exact place to get away from everyone else. NowI get to share this experience with you. What a birthday surprise

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