Q282 · Practice questionTechnology-freeComplex familiar5 marks
QUESTION 282 (5 marks)
A curve satisfies for , and . Angles are in radians.
a)[3 marks]
Determine f(x) explicitly using a substitution.
b)[2 marks]
Determine the limiting values as and . Explain why x=0 is outside the derivative domain.
WORKED SOLUTION
5 marksPractice marking scheme
ANSWER
(a) , for . (b) Limits are 0 and ; the derivative denominator vanishes at x=0.
Worked solution
(a) Put , so . Then . The condition gives , so . Using the complementary inverse-function identity yields the stated expression.
(b) As , and . As , and . At zero the derivative contains in its denominator, so it is undefined, even though f has a finite right-hand limit.
Equivalent justified methods accepted; respect any requested proof method.
Exact values unless specified. Sketches assessed by mathematical features, not artistic quality.
Part a: Choose a valid substitution and transform the differential.
Part a: Integrate to an inverse trigonometric expression.
Part a: Apply the condition to find the constant.
Part b: Evaluate both limiting function values.
Part b: Distinguish the finite function limit from the undefined derivative.
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