Answer only one of the following two alternatives. EITHER It is given that w = cos y and tan y d²y/dx² + (dy/dx)² + 2 tan y dy/dx = 1 + e^(-2x) sec y.
- (i)Show that d²w/dx² + 2dw/dx + w = -e^(-2x).[4]
- (ii)Find the particular solution for y in terms of x, given that when x = 0, y = π/3 and dy/dx = 1/√3.[10]
Mark scheme
Marking points from the official mark scheme (Oct/Nov 2019). The mark or mark type is shown in brackets.
- [B1]
- [B1]
- [M1] Uses substitution to obtain w-x equation, AG.
- [A1]
- [M1] Finds CF.
- [A1]
- [M1] Forms PI and differentiates.
- [A1]
- [A1] States general solution.
- [B1] Uses initial conditions to find constants.
- [M1] Differentiates general solution.
- [M1 A1] Substitutes initial conditions.
- [A1] States particular solution for y in terms of x.
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