题目

设f（x）=（1）求f（x）在点x=1处的左、右极限，在点x=1处f（x）的极限是否存在？（2）f（x）在点x=1处是否连续？（3）求函数f（x）的连续区间？（4）求f（x）、f（x）的值. 答案：解:（1）f（x）=（x-1）=0,f（x）=（2-x）=1.∵f（x）≠f（x）,∴f（x）不存在.（2）由于f（x）在点x=1处的极限不存在，故f（x）在x=1处不连续.（3）函数的连续区间（0，1和（1，3.（4）∵点x=1,x=均在函数的连续区间内，∴f（x）=（x-1）=-.f（x）=（2-x）=0.Tom and his brother ________ some plans for acquiring land and starting in business as market gardeners.A.busied withB.engaged them inC.were occupyingD.were engaged in