A-Level Maths · Pure Mathematics
Parametric Equations
What is it
Parametric equations define x and y separately in terms of a third variable (usually t), rather than expressing y directly in terms of x — commonly used to describe curves and motion.
Why it matters
Parametric equations describe motion and curves that a single y = f(x) equation cannot represent, such as a circle or the path of a projectile, making them essential for mechanics and more advanced curve work.
Exam tip
To convert a parametric equation into a Cartesian one, look for an identity (often sin²+cos²=1) that eliminates the parameter t — spotting the right elimination method quickly saves significant time.
Related topics
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