A-level · Coordinate geometry

Parametric curves and trig identitiesExam-style questions

Converting trigonometric parametric equations to Cartesian form using identities — sin²+cos²≡1 for circles and ellipses, sec²−tan²≡1, and the double-angle formulae — and recognising the curve that results.

16 questions · A-level level · mark scheme and worked solution on each · no sign-up to try

DifficultyAllLevel 2Level 3Level 4Level 5
  1. 1
    A curve has parametric equations x=cos⁡t, y=sin⁡tx = \cos t,\ y = \sin t, 0≤t<2π0 \le t < 2\pi. Find a Cartesian equation of the curve and describe it.
    Level 2 · 2 marksTry it
  2. 2
    A curve has parametric equations x=4cos⁡t, y=4sin⁡tx = 4\cos t,\ y = 4\sin t. Find a Cartesian equation of the curve and state its centre and radius.
    Level 2 · 2 marksTry it
  3. 3
    A curve has parametric equations x=5sin⁡t,  y=5cos⁡tx = 5\sin t, \; y = 5\cos t,   0⩽t<2π\; 0 \leqslant t < 2\pi.

    Find a Cartesian equation of the curve. (2 marks)
    Level 2 · 2 marksTry it