# What is an equation of the line tangent to the graph of #y=cos(2x)# at #x=pi/4#?

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What is an equation of the line tangent to the graph of #y=cos(2x)# at #x=pi/4# ?

What is an equation of the line tangent to the graph of

##### 1 Answer

#### Answer:

#### Explanation:

To find the equation of the tangent line to the curve

Now plug in your value for

This is the slope of the tangent line at

To find the equation of the tangent line, we need a value for

Now use point slope form to find the equation of the tangent line:

Where

This gives us:

Simplifying,

Hope that helps!

graph{(y-cos(2x))(y+2x-pi/2)=0 [-2.5, 2.5, -1.25, 1.25]}