1. Limit Exercises

Exo 1: Basic Limit Calculation

Problem:

\lim_{x \to 0} \frac{\sin(x)}{x}

Solution:

This is a standard limit which is part of the limit formulas:

\lim_{x \to 0} \frac{\sin(x)}{x} = 1

Exo 2: Using L’Hopital’s Rule

Problem:
\lim_{x \to 0} \frac{1 – \cos(x)}{x}

Solution:

This is a \frac{0}{0} indeterminate form, so we can apply L’Hopital’s Rule. We differentiate the numerator and the denominator separately:

Numerator: \frac{d}{dx}[1 – \cos(x)] = \sin(x)

Denominator: \frac{d}{dx}[x] = 1

Now, we compute the new limit:

\Rightarrow \lim_{x \to 0} \frac{\sin(x)}{1} = 0

Exo 3: Limit at Infinity

Problem:

\lim_{x \to \infty} \frac{3x^2 + 5x}{x^2 – 4x + 1}

Solution:

For limits at infinity, we divide both the numerator and denominator by x^2, the highest degree term:
\frac{3x^2 + 5x}{x^2 – 4x + 1} = \frac{3 + \frac{5}{x}}{1 – \frac{4}{x} + \frac{1}{x^2}}
As x \to \infty, the terms with x in the denominator go to zero. Therefore:

\Rightarrow \lim_{x \to \infty} \frac{3 + 0}{1 + 0 + 0} = 3

2. Derivative Exercises

Exo 1: Using the Power Rule

Problem:
Find the derivative of:
f(x) = 3x^4 – 5x^2 + 7x – 2

Solution:

Apply the power rule
\frac{d}{dx}[x^n] = n x^{n-1}

f'(x) = 3 \cdot 4x^3 – 5 \cdot 2x + 7

\Rightarrow f'(x) = 12x^3 – 10x + 7

Exo 2: Product Rule

Problem:
Find the derivative of

f(x) = (2x^3)(x^2 – 1)

Solution:

Use the product rule:

\frac{d}{dx}[u(x) \cdot v(x)] = u'(x) v(x) + u(x) v'(x)

Let

u(x) = 2x^3 \Rightarrow u'(x) = 6x^2
v(x) = x^2 – 1 \Rightarrow v'(x) = 2x

Now apply the product rule:

f'(x) = (6x^2)(x^2 – 1) + (2x^3)(2x)

Simplify:

f'(x) = 6x^4 – 6x^2 + 4x^4

\Rightarrow f'(x) = 10x^4 – 6x^2

Exo 3: Chain Rule

Problem:
Find the derivative of
f(x) = \sin(3x^2)

Solution:

Use the chain rule:

\frac{d}{dx}[f(g(x))] = f'(g(x)) \cdot g'(x)

Let

u = 3x^2 \Rightarrow f(u) = \sin(u)
\frac{d}{dx}[\sin(u)] = \cos(u)
\frac{d}{dx}[3x^2] = 6x
Now, applying the chain rule:

f'(x) = \cos(3x^2) \cdot 6x

\Rightarrow f'(x) = 6x \cos(3x^2)

3. Integration Exercises

Exo 1: Basic Power Rule

Problem:
Find the integral of
f(x) = 5x^3 – 2x^2 + 4x – 1

Solution:


Apply the power rule for integration:

\int x^n \, dx = \frac{x^{n+1}}{n+1} + C \text{ (for } n \neq -1 \text{)}
\int (5x^3 – 2x^2 + 4x – 1) \, dx = \frac{5x^4}{4} – \frac{2x^3}{3} + \frac{4x^2}{2} – x + C

\Rightarrow \int (5x^3 – 2x^2 + 4x – 1) \, dx = \frac{5x^4}{4} – \frac{2x^3}{3} + 2x^2 – x + C

Exo 2: Integration of \frac{1}{x}

Find the integral of:
f(x) = \frac{1}{x}

Solution:


The integral of \frac{1}{x} is:

\int \frac{1}{x} \, dx = \ln|x| + C

Exo 3: Trigonometric Integral

Problem:
Find the integral of

f(x) = \sin(x)

Solution:


The integral of \sin(x) is:

\int \sin(x) \, dx = -\cos(x) + C