Sum Rule of Limits: Proof and Examples [ε-δ Method]

The sum rule of limits says that the limit of the sum of two functions is the same as the sum of the limits of the individual functions. In this post, we will prove the sum/addition rule of limits by the epsilon-delta method.   Question: What is an epsilon-delta proof of the sum law of … Read more

Derivative of root(x)-1

The derivative of root x minus 1 is 1 by 2 root x. In this post, we will prove this derivative formula by the power rule of derivatives as well as by the first principle of derivatives. Derivative of root(x)-1 Formula The Formula for the derivative of root x -1 is given below: Derivative of … Read more

Derivative of xsinx by First Principle

The derivative of xsin x is sin x+x cos x. In this post, we will find the differentiation of x sin x using the first principle of derivatives. The derivative formula of xsin x is given below: $\dfrac{d}{dx}(x \sin x)$ $=\sin x+x\cos x$. We will now prove the above formula. Derivative of xsin x by … Read more

Derivative of Fourth Root of x | 4√x Derivative

The derivative of fourth root of x is 1/(4 x^{3/4}). In this post, we will find the derivative of the fourth root of x using the power rule of derivatives. Note that fourth root of x can be written as Alternatively, one can write it as $x^{\dfrac{1}{4}}$. Derivative of Fourth Root of x To find … Read more

Derivative of x root(x) by First Principle

The derivative of x root x is 3 root(x)/2. In this post, we will find the derivative of x root(x) from first principle. This principle says that the derivative of f(x) is $\dfrac{d}{dx}(f(x))$ $=\lim\limits_{h \to 0}\dfrac{f(x+h)-f(x)}{h}$ $\quad \cdots (I)$ Derivative of x root x by First Principle Let $f(x)=x\sqrt{x}$ in the above formula (I). So … Read more

Derivative of e^2x by First Principle

Answer: The derivative of e^2x by first principle is equal to 2e2x. In this article, we will find the derivative of e to the power 2x using the first principle. Recall that for a function f(x) in one variable x, the derivative of f(x) from first principle is given by the limit below: $\dfrac{d}{dx}(f(x))$ $=\lim\limits_{h … Read more

Derivative of log 3x by First Principle

The derivative of log3x is 1/x. In this post, we will find the derivative of log 3x by first principle. To do so, we will use the following limit formula on logarithm functions: $\lim\limits_{x \to 0} \dfrac{\log(1+x)}{x}=1$ $\quad \cdots (i)$ Derivative of log 3x from First Principle The first principle of derivatives says that the … Read more