Differentiation enables students to analyze how functions behave dynamically. This section specifically explores the sophisticated techniques of parametric and implicit differentiation, which are vital for examining more complex functions and equations.

## Parametric Equations

Parametric equations are a set of functions where $x$ and $y$ are both described in terms of a third variable, often denoted as $t$. This method is particularly useful for characterizing curves that do not lend themselves to simple $x-y$ functional relationships.

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For parametric equations where $x$ and $y$ are functions of $t$:

1. Differentiate $x(t)$ and $y(t)$ with respect to $t$.

2. Calculate $\frac{dy}{dx}$ as $\frac{\frac{dy}{dt}}{\frac{dx}{dt}}$

**Example:**

Differentiate $x = t - e^{2t}$ and $y = t + e^{2t}$:

**Solution:**

Thus,

$\frac{dy}{dx} = \frac{1 + 2e^{2t}}{1 - 2e^{2t}}$Simplified:

$\frac{dy}{dx} = -\frac{2e^{2t} + 1}{2e^{2t} - 1}$## Implicit Functions

Implicit functions are those in which $x$ and $y$ are intermingled within the same equation. They often describe complex shapes and relationships that are not easily separated into distinct functions.

Implicit differentiation for equations with $x$ and $y$ mixed:

1. Treat y as a function of $x$.

2. Differentiate the whole equation with respect to $x$.

3. Solve for $\frac{dy}{dx}$.

**Example:**

Differentiate the implicit function $x^2 + y^2 = xy + 7 $with respect to$x$to find$ \frac{dy}{dx}$.</p><p></p><p><strong>Solution: </strong></p><p>Differentiate each term with respect to$x$, applying the product rule to the term$xy$:</p><p></p>$2x + 2yy' = y + xy'$<p></p><p>Here,$y'$denotes$\frac{dy}{dx}$. Rearrange and solve for$y'$:</p><p></p>$y' = y - 2x$

Rahil spent ten years working as private tutor, teaching students for GCSEs, A-Levels, and university admissions. During his PhD he published papers on modelling infectious disease epidemics and was a tutor to undergraduate and masters students for mathematics courses.