很简单凳首掘
第一小问,最高点和最低点之间横坐标隔半个周期,纵坐标隔两个幅枣核值,所以A=(2-(-4))/2=3;T=2*(8-2)=12;则w=2π/T=π/6;在由方程组2=3sin(π/3+Ф)+c;-4=3sin(4/3π+Ф)+c;可解芹轿得Ф=π/6;c=-1;
第二小问,单调增区间为2kπ-π/2<=π/6*x+π/6<=2kπ+π/2;解得12k-4<=x<=12k+2;
对称中心坐标为π/6*x+π/6=2kπ;解得x=12kπ-1;
对称轴方程为π/6*x+π/6=2kπ+π(k属于z)