+270 Find the equation of the tangent line to y=cos(2x) at x=pi/4
\(f(x) = cos(2x) = cos(2\times \frac{pi}{4} ) = 0\)
So the value of y is zero. Which gives us the point \((\frac{pi}{4}, 0)\)
So to find the slope, we use the derivative:
\(f'(x) = -2sin(2x)\)
\(f'(\frac{pi}{4}) = -2\)
And get that the slope = -2.
Therefore, the solution is:
\(y = -2(x - \frac{pi}{4})\)
