1丨a*b丨=丨a丨丨b丨sinθ∵a=(-3,4),b=(0,2)∴cosθ=a●b/(|a||b|) =8/(5*2)=4/5∴sinθ=√(1-cos²θ)=3/5∴丨a*b丨=丨a丨丨b丨sinθ =5*2*3/5=62(1)f（x）=asinx+bcosx的图像经过点（π/3,0）...