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

7.2 	e) differentiate log_2|x|+sin(x)
	f) differentiate 1/(2x)-3*arccos x
	i) derivative 3*pi^2+6*x^(4/3)
	
7.3 	b) differentiate x^(a)*b^x
	e) ((sin u) / u - ln u * cos u)'
	h) differentiate (x*tan(a))/(1+x^2)+x*ln(x)
	i) differentiate arccos x * arcsin x
		
7.5 	a) 15*t^3*e^t
	   15 e^t t^2 (t + 3) where t = 1
		
7.11 	b) differentiate sqrt((2x+1)/(4x+1))
	d) differentiate cos(-9x+2) + (sin(4x^5))^3
	g) differentiate ln(tan(2x))+ln(cot(2x))
	j) differentiate arccos x * ln(arctan x)

7.13	differentiate k*sqrt(x/m+a/x)

7.19 	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
		
7.20	d) differentiate x^3*e^(x^2)*sin(2x)

7.21 	d) limit (x^5-1)/(x^3-1) where x to 1 
	e) limit ln x / sqrt(x) where x to infty
	f) limit x^2*e^(-x) where x to infty  
	l) limit (x*ln x)/(x+ln x) where x to infty  

7.22	c) limit x^2*ln x where x to 0 

7.23	b) limit x/sqrt(1+x^2) where x to infty