9.2     Plot[Piecewise[{{3x, x<1}, {0, 1.1>x>=1}, {3, 3>=x>=1.1}, {1, x>3}}],{x,0,5}]

9.3     a) plot |x-3|/(x-3)
        d) Plot[Piecewise[{{x^3, x<2}, {6, 2.1>x>=2}, {4x, x>=2.1}}],{x,0,4}]
        e) Plot[Piecewise[{{sin(6x)/(2x), x<-0.1}, {3, 0.1>x>=-0.1}, {sin(6x)/(2x), x>0.1}}],{x,-2,2},{y,-3.5,3.5}]

9.4     a) Plot[Piecewise[{{7x-2, x<=1}, {5x^2, x>1}}],{x,0,2}]
        b) Plot[Piecewise[{{4/3*x^2, x<2}, {2*x+4/3, x>2}}],{x,0,4}]
        c) Plot[Piecewise[{{3+(-1)*x^2, x<1}, {x+1, x>1}}],{x,0,2}]
        d) Plot[Piecewise[{{x-2, x<1}, {cos(pi*x), x>1}}],{x,-1,3}]

9.5     b) plot (sin x)^2/x
        c) plot 2^(1/(3-x)) where x=2..4 y=-100..100
        d) plot (1+x)^(1/x)
        h) plot atan(1/x)

9.7     b) d(2x^2-5)/dx

9.8     e) differentiate log_2|x|+sin(x)
        f) differentiate 1/(2x)-3*arccos x
        i) derivative 3*pi^2+6*x^(4/3)

9.9     b) differentiate x^(a)*b^x
        e) ((sin u) / u - ln u * cos u)'
        g) differentiate (e^x*a^x)/(1+ln(a))
        h) differentiate (x*tan(a))/(1+x^2)+x*ln(x)
        i) differentiate arccos x * arcsin x

9.11    a) differentiate 15*t^3*e^t
        15 e^t t^2 (t + 3) where t = 1

9.15    a) differentiate (4x-3)^5 + (-3x)^2

9.16    b) differentiate sqrt((2x+1)/(4x+1))
        c) differentiate (ln(4x-3))^3
        d) differentiate cos(-9x+2) + (sin(4x^5))^3
        g) differentiate ln(tan(2x))+ln(cot(2x))
        j) differentiate arccos x * ln(arctan x)

9.18    d(k*sqrt(x/m+a/x))/dx

9.21	b) D[sin(x),{x,13}]

9.24    b) d^2(q*e^(q^2))/dq^2
        c) d^3(t/(2+3t))/dt^3 - d^2(2/(2+3t)^2)/dt^2

9.25    d) differentiate x^3*e^(x^2)*sin(2x)