题目

已知，，.（1）求函数的最大值，及此时的取值；（2）在三角形中角的对边分别为，若，，，求三角形的面积. 答案：【答案】(1)函数的最大值为2，此时.(2) .【解析】（1）化简可得：，利用正弦函数的性质列方程可得：时， 取得最大值为，问题得解。（2）由可得：，由余弦定理可求得：，再利用三角形面积公式计算得解。（1）由题可得：，化简得： ，当，即时，此时取得最大值为. （2）由得：，. ，It was the afternoon of December 24, the day before Christmas, but I had to stay to tidy the office. The only thing that ­1 my day was the beautifully decorated Christmas tree in our waiting room and a 2 sent to me by a fellow I was dating—a dozen long-stemmed red roses. Suddenly, our receptionist came and said there was a lady outside that urgently needed to speak with me. As I stepped out, I noticed a young 3 woman with a baby in her arms standing there. 4 , she explained that her husband—a prisoner in a nearby prison—was my next patient. She told me she wasn’t allowed to visit her husband in prison and 5 he had never seen his son. So she 6 me to let her wait here ahead of time. I agreed. After all , it was Christmas Eve. A short time later, her husband arrived—with chains on his feet, cuffs on his hands, and two armed guards 7 him. The woman’s tired face 8 when her husband took a seat beside her. I watched them laugh, cry, and share their 9 . He seemed like a gentle and honest man. At the end of the 10 , the man had to go back and I wished him a Merry Christmas. He smiled and thanked me and said he felt saddened by the fact that he hadn’t been able to get his wife 11 for Christmas. On hearing this, I was 12 with a wonderful idea. I’11 never forget the 13 on both their faces as the prisoner gave his wife the beautiful, long-stemmed red roses. I’m not sure who 14 the most joy—the husband in giving, the wife in receiving, or myself in having the opportunity to share in this 15 moment.1.A.enjoyedB.brightenedC.relaxedD.presented2.A.giftB.regardsC.messageD.package3.A.ordinary-lookingB.good-lookingC.tired-lookingD.frightened-looking4.A.HappilyB.QuietlyC.ExcitedlyD.Nervously5.A.whyB.howC.thatD.when6.A.persuadedB.demandedC.beggedD.pleased7.A.nearB.aroundC.behindD.before8.A.turned paleB.went redC.lit upD.turned away9.A.childB.tearsC.joyD.sorrows10.A.meetingB.appointmentC.discussionD.conversation11.A.somethingB.nothingC.anythingD.everything12.A.encouragedB.struckC.providedD.inspired13.A.sadnessB.happinessC.lookD.smiles14.A.experiencedB.receivedC.gaveD.accepted15.A.unforgettableB.sadC.happyD.special