Given that logₐ pq = 9 and logₐ p²q = 15, find the value of
- (i)logₐ p and of logₐ q,[4]
- (ii)logₚ a + log q a.[2]
Mark scheme
Marking points from the official mark scheme (Oct/Nov 2012). The mark or mark type is shown in brackets.
- [B1] logₐ p + logₐ q = 9
- [B1] 2 logₐ p + logₐ q = 15
- [M1] M1 for solution of the two equations
- [A1] A1 for both
- [B1] Or a⁹ = pq
- [B1] a¹⁵ = p²q
- [M1] M1 for complete solution of the two equations
- [A1] A1 for obtaining both in correct log form
- [M1] Or logₐ p²q – logₐ pq = 6
- [B1] B1 for logₐ (p²q/pq) = 6
- [B1] B1 for logₐ pq = logₐ p + logₐ q = 9
- [A1] A1 for both
- [M1, A1] M1 for change of both to base a logarithm
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 →