Paper 1 · Differentiation
⏱ Tested in 3 exam questions since 2015
Lesson 19 of 21
Differentiation 19 – Tan of the angle made with the horizontal
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- Use the unifying identity slope = tan θ = f'(x) at any point on a curve
- Find the angle a curve makes with the horizontal via θ = tan⁻¹(f'(x))
- Convert to the obtuse angle with 180° − acute (or π − acute in radians)
- Stop at the tan value when the question asks for tan θ, not the angle itself
Most recent exam questions
- 2018 P1 Q3(a)
- 2016 P1 Q8(a)(ii)
- 2015 P1 Q7(b)(ii)
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