Given that ∫ (from a to a+14) (1/3x) dx = ln 2, find the value of the positive constant a.
Mark scheme
Marking points from the official mark scheme (Oct/Nov 2021). The mark or mark type is shown in brackets.
- [M1] Integrate to obtain form k ln x or k ln(3x)
- [A1] Apply limits and obtain ⅓ ln(a+14) – ⅓ ln a = ln 2 or ⅓ ln(3a+42) – ⅓ ln(3a) = ln 2 OE
- [M1] Use one relevant logarithm property correctly
- [M1] Apply correct process to obtain equation without logarithms OE. M0 if incorrect logarithm property used.
- [A1] Obtain (a+14)/a = 8 or equivalent and hence a = 2
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 →