Show that 3 tan 2θ+ tan(θ+45°) = tan²θ+8 tanθ+1 1-tan²θ
- (a)Show that 3 tan 2θ+ tan(θ+45°) = tan²θ+8 tanθ+1 1-tan²θ[4]
- (b)Hence solve the equation 3 tan 2θ+ tan(θ+45°) = 4 for 0° < θ < 180°.[3]
Mark scheme
Marking points from the official mark scheme (May/June 2024). The mark or mark type is shown in brackets.
- [B1] State 3 tan 2θ = 6 tan θ / (1-tan²θ)
- [B1] State tan(θ+45°) = (tan θ + 1) / (1-tan θ)
- [M1] Attempt to express left-hand side in terms of tan θ as a single fraction
- [A1] Confirm (tan²θ+8 tan θ+1)/(1-tan²θ)
- [M1] Solve quadratic equation 5tan²θ+8 tan θ-3=0 to obtain at least one value of θ
- [A1] Obtain 17.4
- [A1] Obtain 117.6
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 →