а) у=3х² - 6√х + 5cosx
y'(x)=3*2*x - 6*(1/2)*(1/√x) - 5*sinx
y'(x)=6x - 3/√x - 5sinx.
б)
(f*g)'=f'*g+f*g'
y=x² * sinx
y'=2x*sinx + x²*cosx.
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√x=x^(1/2); (x^(1/2)'=1/2 * x^(1/2 - 1)=1/2 * x^(-1/2)=1/2 * (1/√x).
(k*x^n)'=k*n*x^(n-1)
(sinx)'=cosx
(cosx)'= -sinx.