Q368 · Practice questionTechnology-freeSimple familiar5 marks
QUESTION 368 (5 marks)
The curve is for .
a)[2 marks]
Use two equal strips to determine the left-endpoint and right-endpoint rectangle estimates.
b)[2 marks]
Use integration to determine the exact area.
c)[1 mark]
Explain why the two rectangle estimates bound the exact area.
WORKED SOLUTION
5 marksPractice marking scheme
ANSWER
a) Left ; right . b) . c) The curve is increasing, so left endpoints give an underestimate and right endpoints an overestimate.
Worked solution
a) The strip width is . Left sum is ; right sum is .
b) .
c) In each strip the increasing function lies above the left-endpoint height and below the right-endpoint height.
Exact answers unless rounding is specified; equivalent forms accepted. Retain unrounded intermediate values.
Obtains the left sum.
Obtains the right sum.
Forms the definite integral.
Evaluates its exact value.
Explains the underestimate and overestimate using monotonicity.
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