题目

已知函数f(x)=x3+bx2+4cx是奇函数，函数f(x)的图象在点(1，f(1))处切线的斜率为-6，且当x=2时，函数f(x)有极值．(Ⅰ)求b的值；(Ⅱ)求函数f(x)的解析式；(Ⅲ)求函数f(x)的单调区间． 答案：答案：解：(Ⅰ)由函数f(x)是奇函数，∴f(-x)=-f(x)，∴b=0．  (Ⅱ)由f(x)=x3+4cx，有f′(x)=ax2+4c且f′(1)=-6，f′(2)=0．∴解得故f(x)=x3-8x． (Ⅲ)∵f(x)=x3-8x，∴f′(x)=2x2-8=2(x+2)(x-2)．  令f′(x)＞0得，x＜-2或x＞2，令f′(x)＜0得-2＜x＜2． ∴函数f(x)的单调增区间为(-∞，-2]，[2，+∞)；单调减区间为[-2，2]．  (或增区间For many years, parties have been an important social event. When 25 people or more gather at a certain location in order to have fun and engage in conversation, it can be considered a party. Parties usually have different drinks and food choices, and music is a large part of the event, very often.Birthday parties are held in honor of an individual who is having a birthday, and presents and gifts are usually brought by attendees(出席者).The song “Happy Birthday to You” is very often sung by partygoers for the person who is having a birthday.There are different kinds of Birthday parties. Adults may have birthday parties in restaurants or nightclubs, while children usually have parties at home or at funhouses. Sometimes children may have parties at water parks or amusement parks as well.Birthday parties may also happen in the manner of a surprise party, where the person having a birthday is not told about the birthday preparations. Surprise parties include guests hiding in a location where the party is to take place, then shouting “surprise!” when the guest of honor enters.Sporting event parties usually take place around a specific sports happening, such as the Super Bowl, the World Cup or the World Series. People gather and eat, drink, and laugh as they talk about the happenings of the games within that sporting event. These types of parties are very lively and usually loud.Nightly socialization parties include house parties and dance parties. House parties sometimes are held by teenagers and young adults of college age in a set location; private houses are often the location of choice. People who manage the music are hired to provide musical entertainment. Usually alcohol is included, resulting in trouble for the attendants of the party.Dance parties include energetic music like disco or pop. People gather at these parties to dance, drink, and have a good time. Usually people at these parities will be of younger ages between 18-28.Title:     【小题1】    Definition  25 people or more gather to have fun and engage in conversation.Different drinks, food choices and   【小题2】   served       【小题3】    Activities Honor the individual   【小题4】Give presents and gifts.  【小题5】  “Happy Birthday to you” for the individual. Location adults: in restaurants or nightclubschildren: at home, funhouses, water parks or amusement parks A surprise party      【小题6】   the person having a birthday about the birthday preparations Hide in the party location. Shout  【小题7】at the guest of honor.  Sporting event parties People gather or watch a specific sports event happening with food, drink and laughter.The parties are  【小题8】  【小题9】    House parties: teenagers and young adults of college ageDance parties: adults between   【小题10】