题目

—Dad, could you buy me a computer like this?—Of course, we can buy_________one than this, but_________it. A．a better, better thanB．a popular, as good asC．a more popular, not as good asD．a cheaper, as good as 答案：D解析:略（本小题满分14分）函数（1）求的周期；（2）求在上的减区间；（3）若，，求的值