13.4    g) integrate [1/x^2-1/(2*sqrt(x))]^2 dx
        h) integrate [(3x^2-4x+5*sqrt(x))/(x^2)] dx

13.5    a) integrate [2^x*5^x+e] dx
        d) integrate [2^x/4^x] dx

13.6    b) integrate [x^4/(x^2+1)] dx
        c) integrate [(1+x)^2/(x(1+x^2))] dx
        d) integrate [(1+sqrt(2))/(sqrt(2-2x^2))] dx

13.7    c) integrate [tan^2x] dx
        d) x*sin(a) + integrate [3*cos(pi+x)] dx

13.9    b) integrate [sin(3x)] dx
        g) integrate [1/(cos(2x-5))^2] dx
        h) integrate [sin^2x] dx

13.10   b) integrate [3^sqrt(x)/sqrt(x)] dx
        d) integrate [(2x+7)/sqrt(1-x^2)] dx

13.11   b) integrate [tan(x)] dx

13.12   c) integrate [(x^2)/(x^2+5)] dx
        f) -2sqrt(2+cos^2(x)) - integrate [(sin(2x))/sqrt(2+cos^2x)] dx
        g) integrate [x*cos(x^2)*(sin(x^2))^2] dx
        h) integrate [1/(x*ln(x)*ln(ln(x)))] dx

13.15   a) 2/5*sqrt(1-x)^5-2/3*sqrt(1-x)^3-integrate [x*sqrt(1-x)] dx
        c) integrate [sqrt(1-x^2)] dx
        d) integrate [1/sin(2x)] dx

13.16   b) integrate [1/(sqrt(e^x-1))] dx
        c) integrate [3sqrt(x)/(1+x^(3/4))] dx