Question:
Find the slope of the tangent to the curve $y=3 x^{4}-4 x$ at $x=4$.
Solution:
The given curve is $y=3 x^{4}-4 x$.
Then, the slope of the tangent to the given curve at x = 4 is given by,
$\left.\left.\frac{d y}{d x}\right]_{x=4}=12 x^{3}-4\right]_{x=4}=12(4)^{3}-4=12(64)-4=764$