It's hard to type and hard to read the "inverse tangent" function, as you've seen (above).
So, use "arctan x" instead.
Then the problem becomes: "differentiate cos (arctan x)."
You must apply first the rule for differentiating the cosine function, and next apply the rule for differentiating the arctan function:
(d/dx) cos (arctan x) = - sin (arctan x) * [1/(1+x^2)]
5n =70
5 x 14 = 70
hope this helped :)
Answer: 
Step-by-step explanation:
Substitute the value of the <u><em>variable</em></u> into the <u><em>equation</em></u> and simplify.
I evaluate and found the exact value: 4

If you want me to Find the Linearization at h=5: Use the formula
to find the linearization.
Answer(Find the Linearization at h=5): 