在△ABC中，a、b、c分别是角A、B、C所对的边，满足a2+c2-b2=ac．
（1）求角B的大小；
（2）若x∈[0，π），求函数f（x）=sin（x-B）+sinx的值域．
（1）在△ABC中，由余弦定理得cosB=
=a2+c2-b2 2ac 1 2
又∵B∈(0，π)，∴B=
；π 3
（2）f(x)=sin(x-
)+sinx=π 3
sinx-3 2
cosx=3 2
sin(x-3
)π 6
∵0≤x＜π，则-
≤x-π 6
＜π 6 5π 6
∴sin(x-
)∈[-π 6
，1]1 2
D. R. Gaul Middle School is in Union, Maine, a blueberry-farming town where the summer fair finds kids competing in pig scrambles(争夺) and pie-eating contests. Gaul, with about 170 seventh- and eighth-graders, has its own history of lower level academic achievement. One likely reason: Education beyond the basic requirements hasn't always been a top priority(优先) for families who've worked the same land for generations. Here, few adults have college degrees, and outsiders(局外人) (teachers included) are often kept at a respectful distance. Since 2002, Gaul's students have been divided into four classes, each of them taught almost every subject by two teachers. The goal: To find common threads across disciplines to help students create a big picture that gives fresh meaning and context to their class work -- and sparks(激发) motivation for learning. Working within state guidelines, each team makes its individual schedules and lesson plans, incorporating non-textbook literature, hands-on lab work and field trips. If students are covering the Civil War in social studies, they're reading The Red Badge of Courage or some other period literature in English class. In science, they study the viruses and bacteria that caused many deaths in the war. Team teaching isn't unusual. About 77 percent of middle schools now employ some form of it, says John Lounsbury, consulting editor for the National Middle School Association. But most schools use four- or five-person teams, which Gaul tried before considering two-person teams more effective. Gaul supports the team concept by "looping" classes (跟班) so that the same two teachers stick with the same teens through seventh and eighth grades. Combining teams and looping creates an extremely strong bond between teacher and student. It also, says teacher Beth Ahlholm, "allows us to build an excellent relationship with parents." Ahlholm and teammate Madelon Kelly are fully aware how many glazed looks they see in the classroom, but they know 72 percent of their eighth-graders met Maine's reading standard last year -- double the statewide average. Only 31 percent met the math standard, still better than the state average (21 percent). Their students also beat the state average in writing and science. And in2006, Gaul was one of 47 schools in the state to see testing gains of at least 20 percent in four of the previous five years, coinciding roughly with team teaching's arrival.
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