2015届高三学子们已经踏上远航的征程.暑假时他们曾陆续返校与老师告别,在交流中,他们中的一部分学生还是沉迷于2015年江苏卷第19题第二问上,仍再追问:老师,这题究竟该怎么做?也有的新高三的学生在问这个问题,于是我们就此题展开交流.生甲(华东师范大学):已知函数f(x)=x~3+ax~2+b(a,b∈R);(1)试讨论f(x)的单调性;(2)若b=c-a(实数c是与a无关常 2015 high school students have embarked on a voyage journey.When the summer vacation they have to return to school with the teacher to say goodbye, in the exchange, some of them are still addicted to 2015 Question 19 Question No. : Teacher, how to do this question? Some new high school students are asking this question, so we talk about the exchange .Birth A (East China Normal University): Known function f (x) = x ~ 3 + ax ~ 2 + b (a, b∈R); (1) Discuss the monotonicity of f (x); (2) If b = ca