Moderate -0.8 This is a straightforward application of the general solution formula for sin θ = sin α, requiring students to recall that solutions are θ = α + 360n° or θ = 180° - α + 360n°, then solve two linear equations for x. While it's Further Maths content, it's a routine procedural question with no conceptual challenges beyond remembering the formula.
Introduction of \(90n°\), or \(360n°\) or \(180n°\)
M1
Or \(\frac{\pi n}{2}\) or \(2\pi n\) or \(\pi n\)
GS \((10 + 90n)°,(30 + 90n)°\)
A1√
OE if one numerical error or omission of 2nd soln
Total for Q3: 5 marks
One solution is $x = 10°$ | B1 | Pl by general formula
Use of sin $130° =$ sin $50°$ | M1 | OE
Second solution is $x = 30°$ | A1 | OE
Introduction of $90n°$, or $360n°$ or $180n°$ | M1 | Or $\frac{\pi n}{2}$ or $2\pi n$ or $\pi n$
GS $(10 + 90n)°,(30 + 90n)°$ | A1√ | OE if one numerical error or omission of 2nd soln
**Total for Q3: 5 marks**
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