Show that 3 sin 2θ cot θ = 6 cos² θ.

Mark scheme

Marking points from the official mark scheme (May/June 2020). The mark or mark type is shown in brackets.

1. [B1] Use at least one of sin 2θ = 2 sin θ cos θ and cot θ = cos θ / sin θ
2. [B1] Use both and conclude 6cos² θ AG
3. [M1] Attempt solution of cos² θ = 5/6 to find at least one value
4. [A1] Obtain 0.421
5. [A1] Obtain 2.72
6. [M1] Express integrand in form a + b cos x
7. [A1] Obtain correct integrand 3 + 3 cos x
8. [*M1] Integrate to obtain px + q sin x
9. [DM1] Apply limits correctly
10. [A1] Obtain 3/4π + 3 - 3/√2 or exact equivalent