Calculate the first derivative ($\frac{dy}{dx}$) and second derivative ($\frac{d^2y}{dx^2}$) for parametric equations $x(t)$ and $y(t)$, with step-by-step solutions.
⚠️ Note: Use exp(t) for eᵗ, not e^t. Use ln(t) or log(t) for natural log.
Computing $\frac{dx}{dt}$, $\frac{dy}{dt}$, and the second derivative...
Plot of the parametric curve $(x(t), y(t))$ for $t \in [-10, 10]$.
Parametric equations define coordinates $(x, y)$ in terms of a third variable, typically $t$ (representing time or a parameter). Finding $\frac{dy}{dx}$ and $\frac{d^2y}{dx^2}$ requires the chain rule applied carefully to each component.
The slope of a parametric curve at any point is the ratio of the rate of change of $y$ to the rate of change of $x$ — both with respect to the parameter $t$:
The second derivative gives the concavity of the parametric curve. A common mistake is squaring the first derivative — the correct formula differentiates $\frac{dy}{dx}$ with respect to $t$, then divides by $\frac{dx}{dt}$ again:
For $x(t) = \cos(t)$, $y(t) = \sin(t)$:
A parametric derivative is the derivative $\frac{dy}{dx}$ of a curve defined by parametric equations $x(t)$ and $y(t)$. Rather than having $y$ as a direct function of $x$, both are functions of a parameter $t$. The derivative is computed using the chain rule: $\frac{dy}{dx} = \frac{dy/dt}{dx/dt}$.
Differentiate $x(t)$ with respect to $t$ to get $\frac{dx}{dt}$, and differentiate $y(t)$ with respect to $t$ to get $\frac{dy}{dt}$. Then divide: $\frac{dy}{dx} = \frac{dy/dt}{dx/dt}$. This is valid as long as $\frac{dx}{dt} \neq 0$.
The second derivative is $\frac{d^2y}{dx^2} = \frac{\frac{d}{dt}\!\left(\frac{dy}{dx}\right)}{\frac{dx}{dt}}$. You differentiate the first derivative $\frac{dy}{dx}$ (which is a function of $t$) with respect to $t$, then divide by $\frac{dx}{dt}$ again.
The derivative $\frac{dy}{dx}$ is undefined when $\frac{dx}{dt} = 0$. This means the parametric curve has a vertical tangent line at that parameter value $t$. Our calculator detects this automatically and displays a clear warning.
Provide your visitors with this Parametric Derivative Calculator. Copy the code below to integrate it into your site.
Click the text area above to instantly copy the embed code.
Ready to Practice?
Download our free Parametric Derivative Worksheet — Parametric Derivatives Mastery Worksheet.