3. This question relates to numerical integration a) Sketch the curve y=0.8x3 between x=0 and x=5. On your sketch clearly mark the area indicated by the following expression and evaluate the expression. I=140.8x3dx [5 marks] b) Using the trapezoidal rule, given below, determine the area under the curve y=0.8x3 between x=1 and x=4 dividing the area into n=4 sections, each with width h=0.75. Include a sketch and explain your work. abf(x)dx=2h(f(a)+2f(a+h)+2f(a+2h)+2f(a+3h)+f(b))withh=nba [15 ma c) Compare the results obtained in part a and part b of this question and explain any difference and how you would increase the accuracy of the numerical solution