题目

—It's ___________ today. Why not have a picnic (野餐) outside?—Sounds great! Let's ask the twins to join us. A . sunny B . windy C . cloudy D . snowy 答案：A已知函数f(x)=a+2x2x+1(a∈R)是定义在R上的奇函数．（1）求实数a的值；（2）解关于x的不等式f（x2-tx）＞f（2x-2t）（其中t∈R）．