hexiao7
幼苗
共回答了19个问题采纳率:94.7% 举报
1、a垂直b→ab=0x0c,|a+b|=√(a+b)²=√a²+2ab+b²=√sin²x+1+0+cos²x+1/4=√9/4=3/2x0c
2、f(x)=(cosx*sinx-sinx^2,3/2)=(1/2*sin2x-1/2+1/2cos2x,3/2);
f(x)=a(b-a)
=(sinx,1)*(cosx-sinx,-3/2)
=sinxcosx-sin²x-3/2
=1/2sin2x-1/2+1/2cos2x-3/2
=√2sin(2x+π/4)-2
所以最小正周期是π
1年前
8