Show that (1/(secx-1)) + (1/(secx+1)) = 2 cotx cosecx.
- (a)Show that (1/(secx-1)) + (1/(secx+1)) = 2 cotx cosecx.[4]
- (b)Hence solve the equation (1/(secx-1)) + (1/(secx+1)) = 3 secx for 0° < x < 360°.[4]
Mark scheme
Marking points from the official mark scheme (Oct/Nov 2021). The mark or mark type is shown in brackets.
- [M1]
- [A1]
- [A1]
- [A1] Fully correct justification of given answer: 2cotxcosecx
- [B1] 3tan²x = 2 oe or better, soi or 5cos²x = 3 oe or better, soi or 5sin²x = 2 oe or better, soi
- [M1] FT an equation of the form a tan²x = b, a > 0, b > 0 or p sin²x = q or p cos²x = q where p > 0, q > 0 and p > q
- [A2] no extras in range
- [A1] for any two correct answers
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 →