6.1     a) plot sqrt(x), x^2
        b) plot -sqrt(x), x^2
        c) plot log(x-1), 10^x+1
        d) plot 2-10^(x-1) , 1+log|x-2|
        c) plot 3*sin(2*x) where x from -pi/4 to 0
        f) plot 1+arccos(1-x) plot 1-cos(x-1) where x from 1 to pi +1

6.2     b) plot 2^x
        d) plot x^2
        f) plot sin x

6.3     a) Plot[y= x-5+ln(x-5)]
        ParametricPlot[{t+5},{t+ln t}]

6.4     a) Plot[x = ln(y-sin x)], Plot{y=e^x+sin x}
        b) Plot[y^2-2xy+x^2-4=0], Plot{y=-2+x}, Plot{y=2+x}

6.6     300*1.03^10

6.8     b) (ln(1/e^(3x)) - (-3x)
        d) (4ln(sqrt(x))+6ln(x^(1/3))) - ln x^4
        e) 16^(log_2(48^(1/4))-1) - 3
        f) e^(2ln(cos(x)))+(ln(e^sin(x)))^2 - 1
        h) log(log(sqrt(10^(1/5)))) - (-1)

6.9     b) 3^(1-log_3(7))+5^(log_5(8)+1)-2.4^(log_(2.4)10+1) - (16+3/7)
        d) 4*(81^(1/4-1/2*log_9(4))+25^log_125(8)) - 19

6.8     -5/4*ln(1.5/4999)
        5000/(1+4999*e^(-0.8t)) where t= 10,11
        plot 5000/(1+4999*e^(-0.8t)) where t from 0 to 20