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Partial Derivative Calculator

Calculate partial derivatives step by step

This online calculator will calculate the partial derivative of the function, with steps shown. You can specify any order of integration.

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Hint: type x^2,y to calculate `(partial^3 f)/(partial x^2 partial y)`, or enter x,y^2,x to find `(partial^4 f)/(partial x partial y^2 partial x)`.

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Solution

Your input: find $$$\frac{\partial}{\partial x}\left(81 x^{2} + y^{2}\right)$$$

The derivative of a sum/difference is the sum/difference of derivatives:

$${\color{red}{\frac{\partial}{\partial x}\left(81 x^{2} + y^{2}\right)}}={\color{red}{\left(\frac{\partial}{\partial x}\left(81 x^{2}\right) + \frac{\partial}{\partial x}\left(y^{2}\right)\right)}}$$

Apply the constant multiple rule $$$\frac{\partial}{\partial x} \left(c \cdot f \right)=c \cdot \frac{\partial}{\partial x} \left(f \right)$$$ with $$$c=81$$$ and $$$f=x^{2}$$$:

$${\color{red}{\frac{\partial}{\partial x}\left(81 x^{2}\right)}} + \frac{\partial}{\partial x}\left(y^{2}\right)={\color{red}{\left(81 \frac{\partial}{\partial x}\left(x^{2}\right)\right)}} + \frac{\partial}{\partial x}\left(y^{2}\right)$$

Apply the power rule $$$\frac{\partial}{\partial x} \left(x^{n} \right)=n\cdot x^{-1+n}$$$ with $$$n=2$$$:

$$81 {\color{red}{\frac{\partial}{\partial x}\left(x^{2}\right)}} + \frac{\partial}{\partial x}\left(y^{2}\right)=81 {\color{red}{\left(2 x^{-1 + 2}\right)}} + \frac{\partial}{\partial x}\left(y^{2}\right)=162 x + \frac{\partial}{\partial x}\left(y^{2}\right)$$

The derivative of a constant is 0:

$$162 x + {\color{red}{\frac{\partial}{\partial x}\left(y^{2}\right)}}=162 x + {\color{red}{\left(0\right)}}$$

Thus, $$$\frac{\partial}{\partial x}\left(81 x^{2} + y^{2}\right)=162 x$$$

Answer: $$$\frac{\partial}{\partial x}\left(81 x^{2} + y^{2}\right)=162 x$$$