Derivative of a Constant
Let f(x) = k be the given function.
Then, we have
Therefore derivative of a constant is 0.
or
Derivative of xn where n is any integer




Note:
(i) The result is also true for any real exponent n.
(ii) Derivative of xn, where n is any real number, can be obtained by subtracting 1 from the exponent n and multiply the result by n.Example:

Derivative of a Constant of a Function
Let f (x) = k u(x)
where k is a constant and u = u(x), x
R, be a differential function of x. We then have


Derivative of Exponential Function
If f(x) = ex, then



Derivative of the Logarithmic Function
Let f(x) = loge x (x > 0). Then



Note:
Derivative of loga x (x > 0).

Derivative of sin x
Let f(x) = sin x. Then, we have


Remark:
Similarly, one can prove that

Derivative of tan x
Let f(x) = tan x. Then, we have




Remark:
Similarly, we can prove that

Derivative of sec x
Let f(x) = sec x. Then, we have





Derivative of Sum of Two Functions
Let y = u + v, where u and v are differentiable functions of x.


or (u + v)' = u' + v'
Note:
In general, the result is true for the sum of any number of functions.
Example:
Differentiate the following function with respect to x.

Suggested answer:


