Without using a calculator, express (2 + √5)² / (√5 – 1) in the form a + b√5, where a and b are constants to be found.
- Without using a calculator, express (2 + √5)² / (√5 – 1) in the form a + b√5, where a and b are constants to be found.[4]
Mark scheme
Marking points from the official mark scheme (May/June 2014). The mark or mark type is shown in brackets.
- [M1] rationalise the denominator to get (2+√5) (√5+1) / 5-1 or better
- [M1] or squaring to get (4+4√5+5) / √5-1 or better
- [A1 + A1] or rationalising the denominator to get their(9+4√5)(√5+1) / 5-1 or better correct simplification Allow 29+13√5 / 4 etc.
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 →