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# Find an equation of the tangent line to the curve at the given point.$y = \sqrt[4]{x} - x, (1,0)$

## $$y= \sqrt[4]{x}-x$$ First, rewrite $\sqrt[4]{x}$ in indices form using the property $\sqrt[a]{b}= b^{\frac{1}{a}}$$y= x^{\frac{1}{4}} -x$$Recall, that the first derivative of an equation gives the equation of the gradient at any point$x$, therefore differenciate the equation with respect to$x$.$$\frac{dy}{dx}=\frac{d}{dx}(x^{\frac{1}{4}})- \frac{d}{dx}(x)$$Using the power rule:$$\frac{dy}{dx}= \frac{1}{4}x^{-\frac{3}{4}}-1$$To find the gradient, subctitute$x=1$$\frac{dy}{dx}= \frac{1}{4}(1)^{-\frac{3}{4}}-1$$Rewrite using laws of indices:$$\frac{dy}{dx}=\frac{1}{4}\sqrt[4]{(1)^{-3}}-1$$Evaluate the gradient:$$m=\frac{1}{4}(1)-1= \frac{-3}{4}$$The point slope for is$$y-y_1=m(x-x_1)$$Substitute $m= -\frac{3}{4}$ and $y_1=0$ and \$x_1=1$$y-0= -\frac{3}{4}(x-1)$$

Derivatives

Differentiation

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##### Kristen K.

University of Michigan - Ann Arbor

##### Samuel H.

University of Nottingham

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### Video Transcript

he had square. So when you read here, so we have why is equal to X to the 1/4 power minus acts. This can be rewritten as follows. So we're gonna different she using the power roll. So we have to you. By over D X is equal to 1/4 ex to the negative 34 It's minus one and using the slope of the tangent at 10 Do you I over D X is equal to negative three ports, and the equation of the tension is lie minus zero. It's equal to negative 3/4 times X minus one, which is equal to negative 3/4 x flus tree forts.

#### Topics

Derivatives

Differentiation

##### Kristen K.

University of Michigan - Ann Arbor

##### Samuel H.

University of Nottingham

Lectures

Join Bootcamp