It is given that ∫_a^(a³) (10 / (2x+1)) dx = 7, where a is a constant greater than 1.
- (a)Show that a = ³√(0.5e^(1.4) (2a+1) - 0.5).[5]
- (b)Use an iterative formula, based on the equation in part (a), to find the value of a correct to 3 significant figures. Use an initial value of 2 and give the result of each iteration to 5 significant figures.[3]
Mark scheme
Marking points from the official mark scheme (Oct/Nov 2024). The mark or mark type is shown in brackets.
- [5] Obtain integral of form kln(2x+1) *M1
- Obtain correct 5ln(2x+1) A1
- Apply limits correctly and equate to 7 DM1
- Apply appropriate logarithm property to reach at least a³ =... DM1
- Confirm a = 0.5e^1.4 (2a+1) - 0.5 A1 AG – necessary detail needed.
- [3] Use iterative process correctly at least once M1
- Obtain final answer 2.18 A1 Answer required to exactly 3 sf.
- Show sufficient iterations to 5 sf to justify answer or show a sign change in the interval [2.175, 2.185] A1
Write your answer and get it marked
On Oracle Prep you can write or photograph your own answer and have it marked by AI against this mark scheme, with feedback on what you missed.
Sign up free →