求下列函数的导数：(1)y=(√x-2)^2 (2)y=cosx/2(sinx/2-cosx/2)

(1)如果是y=(√(x-2))^2,那么y’=2(√x-2)•1/[2(√x-2)]=1如果是y=(√x-2)^2,那么y’=2(√x-2)•1/[2√x]=1-2/√x(2)先恒等变换,特别注意：导数化简y=cosx/2(sinx/2-cosx/2)= cosx/2sinx/2-cos^2 x/2=1/2•sinx-1/2-1/2•cosxy’=1/2(sinx+cosx)=√2/2•sin(x+π/4)（3）y’=1/ln2•1/(ax^3)•3ax^2=3/(xln2)