Finals week is coming, and if you’re staring at your Calculus 1 notes wondering where to even begin — this guide is for you.
I’ve broken down every major topic you need to know, with clear explanations, worked examples, and tips that actually help. No fluff, no overwhelming walls of text — just what you need to pass (or ace!) your Calc 1 final.
Here’s everything we’ll cover:
📚 Table of Contents
- Limits and Continuity
- Derivatives — Rules and Techniques
- Applications of Derivatives
- Integration Basics
- Common Mistakes to Avoid
- Finals Week Study Strategy
- Practice Problems
Let’s get into it. 👇
1. Limits and Continuity
Limits are the foundation of everything in calculus. Before you can understand derivatives or integrals, you need to understand limits.
What is a Limit?
A limit asks: “What value does f(x) approach as x gets close to some number?”
It doesn’t matter what happens exactly AT that point — only what happens as you get close to it.
Essential Limit Laws
Sum Rule:
$$\lim_{x \to a} [f(x) + g(x)] = \lim_{x \to a} f(x) + \lim_{x \to a} g(x)$$
Product Rule:
$$\lim_{x \to a} [f(x) \cdot g(x)] = \lim_{x \to a} f(x) \cdot \lim_{x \to a} g(x)$$
Sine Limit:
$$\lim_{x \to 0} \frac{\sin(x)}{x} = 1$$
Reciprocal at Infinity:
$$\lim_{x \to \infty} \frac{1}{x} = 0$$
✏️ Example 1 — Direct Substitution (Easiest Method)
Problem: Find \( \lim_{x \to 3} (x^2 + 2x – 1) \)
Solution: Just plug in x = 3:
$$3^2 + 2(3) – 1 = 9 + 6 – 1 = 14$$
✅ Answer: 14
Watch another example:
✏️ Example 2 — Factoring Method (When You Get 0/0)
Problem: Find \( \lim_{x \to 2} \frac{x^2 – 4}{x – 2} \)
Solution: Plugging in gives 0/0 — that means we need to factor first.
$$\lim_{x \to 2} \frac{(x+2)(x-2)}{x-2} = \lim_{x \to 2} (x+2) = 4$$
✅ Answer: 4
Watch another example:
✏️ Example 3 — Limits at Infinity
Problem: Find \( \lim_{x \to \infty} \frac{3x^2 + 2x}{x^2 – 5} \)
Solution: Divide everything by the highest power \( x^2 \):
$$\lim_{x \to \infty} \frac{3 + \frac{2}{x}}{1 – \frac{5}{x^2}} = \frac{3 + 0}{1 – 0} = 3$$
✅ Answer: 3
Watch another example:
🎯 Limit Quick Tips
- Always try direct substitution first
- Get 0/0? Try factoring or L’Hôpital’s Rule
- Limits at infinity? Divide by the highest power of x
- Left limit ≠ Right limit? The limit does not exist (DNE)
2. Derivatives — Rules and Techniques
Derivatives measure the rate of change of a function. Think of it as the slope of a curve at any given point.
The Rules You MUST Know
Power Rule:
$$\frac{d}{dx}[x^n] = nx^{n-1}$$
Product Rule:
$$\frac{d}{dx}[f(x)g(x)] = f'(x)g(x) + f(x)g'(x)$$
Quotient Rule:
$$\frac{d}{dx}\left[\frac{f(x)}{g(x)}\right] = \frac{f'(x)g(x) – f(x)g'(x)}{[g(x)]^2}$$
Chain Rule:
$$\frac{d}{dx}[f(g(x))] = f'(g(x)) \cdot g'(x)$$
Common Derivatives to Memorize
$$\frac{d}{dx}[\sin(x)] = \cos(x)$$
$$\frac{d}{dx}[\cos(x)] = -\sin(x)$$
$$\frac{d}{dx}[e^x] = e^x$$
$$\frac{d}{dx}[\ln(x)] = \frac{1}{x}$$
$$\frac{d}{dx}[\tan(x)] = \sec^2(x)$$
✏️ Example 4 — Power Rule
Problem: Find \( \frac{d}{dx}[x^5 + 3x^2 – 7x + 2] \)
$$5x^4 + 6x – 7$$
✅ Answer: \( 5x^4 + 6x – 7 \)
Watch another example:
✏️ Example 5 — Product Rule
Problem: Find \( \frac{d}{dx}[x^2 \sin(x)] \)
Let f(x) = x² and g(x) = sin(x)
$$f'(x)g(x) + f(x)g'(x) = 2x\sin(x) + x^2\cos(x)$$
✅ Answer: \( 2x\sin(x) + x^2\cos(x) \)
Watch another example:
✏️ Example 6 — Chain Rule
Problem: Find \( \frac{d}{dx}[(3x^2 + 1)^5] \)
Outer function: u⁵ → derivative = 5u⁴
Inner function: 3x² + 1 → derivative = 6x
$$5(3x^2 + 1)^4 \cdot 6x = 30x(3x^2 + 1)^4$$
✅ Answer: \( 30x(3x^2 + 1)^4 \)
Watch another example:
✏️ Example 7 — Quotient Rule
Problem: Find \( \frac{d}{dx}\left[\frac{x^2 + 1}{x – 3}\right] \)
$$\frac{2x(x-3) – (x^2+1)(1)}{(x-3)^2} = \frac{x^2 – 6x – 1}{(x-3)^2}$$
✅ Answer: \( \frac{x^2 – 6x – 1}{(x-3)^2} \)
Watch another example:
🎯 Derivative Quick Tips
- See a function inside a function? That’s Chain Rule
- Two functions multiplied? That’s Product Rule
- One function divided by another? That’s Quotient Rule
- Always simplify your final answer
3. Applications of Derivatives
This is where calculus gets real. Derivatives aren’t just about rules — they tell us about the shape and behavior of functions.
Finding Critical Points
Critical points are where f'(x) = 0 or f'(x) is undefined. They tell you where a function has a maximum, minimum, or neither.
✏️ Example 8 — Finding Critical Points
Problem: Find the critical points of \( f(x) = x^3 – 6x^2 + 9x \)
$$f'(x) = 3x^2 – 12x + 9 = 3(x^2 – 4x + 3) = 3(x-1)(x-3)$$
Set f'(x) = 0: x = 1 and x = 3
✅ Answer: Critical points at x = 1 and x = 3
Optimization Problems — 5 Easy Steps
- Draw a diagram and label everything
- Write what you’re maximizing or minimizing
- Write the constraint equation
- Substitute to get one variable, then take the derivative
- Set derivative = 0 and solve
Watch another example:
✏️ Example 9 — Optimization
Problem: You have 100 feet of fence to enclose a rectangle. What dimensions give the maximum area?
Constraint: \( 2x + 2y = 100 \) → \( y = 50 – x \)
Area: \( A = x(50 – x) = 50x – x^2 \)
$$A’ = 50 – 2x = 0 \Rightarrow x = 25$$
✅ Answer: 25 ft × 25 ft (a square always maximizes area!)
Related Rates — 5 Easy Steps
- Draw a diagram
- Write down what you know and what you’re finding
- Write an equation connecting the variables
- Differentiate both sides with respect to time (t)
- Plug in known values and solve
Watch another example:
4. Integration Basics
Integration is the reverse of differentiation. If derivatives find the slope, integrals find the area under a curve.
The Fundamental Theorem of Calculus
$$\int_a^b f(x)\,dx = F(b) – F(a)$$
Where F'(x) = f(x). This is the most important theorem in all of Calculus 1.
Basic Integration Rules
$$\int x^n\,dx = \frac{x^{n+1}}{n+1} + C \quad (n \neq -1)$$
$$\int e^x\,dx = e^x + C$$
$$\int \sin(x)\,dx = -\cos(x) + C$$
$$\int \cos(x)\,dx = \sin(x) + C$$
$$\int \frac{1}{x}\,dx = \ln|x| + C$$
✏️ Example 10 — Basic Indefinite Integral
Problem: Find \( \int (3x^2 + 4x – 5)\,dx \)
$$x^3 + 2x^2 – 5x + C$$
✅ Answer: \( x^3 + 2x^2 – 5x + C \)
⚠️ Never forget the + C! It costs you points every single time.
Watch another example:
✏️ Example 11 — Definite Integral
Problem: Evaluate \( \int_1^3 (2x + 1)\,dx \)
$$F(x) = x^2 + x$$
$$F(3) – F(1) = (9 + 3) – (1 + 1) = 12 – 2 = 10$$
✅ Answer: 10
Watch another example:
U-Substitution — The Most Important Integration Technique
Use this when you see a function and its derivative sitting next to each other.
Steps:
- Pick u (usually the “inside” function)
- Find du
- Substitute everything
- Integrate
- Substitute back
✏️ Example 12 — U-Substitution
Problem: Find \( \int 2x(x^2 + 1)^5\,dx \)
Let \( u = x^2 + 1 \), then \( du = 2x\,dx \)
$$\int u^5\,du = \frac{u^6}{6} + C = \frac{(x^2+1)^6}{6} + C$$
✅ Answer: \( \frac{(x^2+1)^6}{6} + C \)
Watch another example:
5. Common Mistakes to Avoid ⚠️
These are the mistakes that cost students the most points. Read them carefully — and don’t be that person.
- ❌ Forgetting the Chain Rule: d/dx[sin(3x)] = 3cos(3x), not just cos(3x)
- ❌ Forgetting + C: Every indefinite integral needs it
- ❌ Wrong trig derivative: d/dx[cos(x)] = −sin(x) (don’t drop the negative!)
- ❌ Wrong power rule for integrals: ∫x² dx = x³/3 + C, not x³
- ❌ Not factoring before limits: Always simplify 0/0 forms first
- ❌ Skipping steps: Show your work — partial credit is real
- ❌ Not reading the question: “Find f'(x)” vs “Find f'(2)” are different things
6. Finals Week Study Strategy
Knowing the math is only half the battle. Here’s how to actually prepare so it sticks.
7-Day Study Plan
Day 7: Gather all notes, identify weak topics, print formula sheet
Days 6–5: Review each topic, redo problems you got wrong
Days 4–3: Take a full practice exam under timed conditions
Day 2: Focus on weak areas, teach concepts out loud
Day 1: Light review only, organize materials, sleep 8 hours
Exam day: Good breakfast, arrive early, stay calm
Study Tips That Actually Work
- Do problems, don’t just read notes. Spend 80% of your time solving problems.
- Teach it out loud. If you can explain it, you understand it.
- Use spaced repetition. A little bit every day beats an all-nighter.
- Check your work. Take the derivative of your integral to verify it.
7. Practice Problems — Test Yourself!
Try each problem on your own first — then click “Show Answer” to check your work. Seriously, attempt it before peeking! 😄
📌 Limits
1. Find \( \lim_{x \to 4} \frac{x^2 – 16}{x – 4} \)
👉 Show Answer
Factor the numerator:
$$\frac{(x+4)(x-4)}{x-4} = x + 4$$
Plug in x = 4:
$$4 + 4 = 8$$
✅ Answer: 8
2. Find \( \lim_{x \to \infty} \frac{5x^3 + 2x}{2x^3 – x^2} \)
👉 Show Answer
Divide everything by the highest power \( x^3 \):
$$\lim_{x \to \infty} \frac{5 + \frac{2}{x^2}}{2 – \frac{1}{x}} = \frac{5 + 0}{2 – 0} = \frac{5}{2}$$
✅ Answer: 5/2
3. Find \( \lim_{x \to 3} \frac{x^2 – 9}{x – 3} \)
👉 Show Answer
Factor the numerator:
$$\frac{(x+3)(x-3)}{x-3} = x + 3$$
Plug in x = 3:
$$3 + 3 = 6$$
✅ Answer: 6
📌 Derivatives
4. Find f'(x) if \( f(x) = x^4 – 3x^2 + 7 \)
👉 Show Answer
Apply the power rule to each term:
$$f'(x) = 4x^3 – 6x$$
✅ Answer: \( 4x^3 – 6x \)
5. Find dy/dx if \( y = (2x + 1)^3 \)
👉 Show Answer
Use the Chain Rule — outer function is u³, inner function is (2x + 1):
$$\frac{dy}{dx} = 3(2x+1)^2 \cdot 2 = 6(2x+1)^2$$
✅ Answer: \( 6(2x+1)^2 \)
6. Find dy/dx if \( y = \frac{x^2}{x+1} \)
👉 Show Answer
Use the Quotient Rule where f(x) = x² and g(x) = x + 1:
$$\frac{dy}{dx} = \frac{2x(x+1) – x^2(1)}{(x+1)^2} = \frac{2x^2 + 2x – x^2}{(x+1)^2} = \frac{x^2 + 2x}{(x+1)^2}$$
✅ Answer: \( \frac{x^2 + 2x}{(x+1)^2} \)
7. Find f'(x) if \( f(x) = x^2 \sin(x) \)
👉 Show Answer
Use the Product Rule where f(x) = x² and g(x) = sin(x):
$$f'(x) = 2x\sin(x) + x^2\cos(x)$$
✅ Answer: \( 2x\sin(x) + x^2\cos(x) \)
8. Find f'(x) if \( f(x) = e^{3x} \)
👉 Show Answer
Use the Chain Rule — outer function is eᵘ, inner function is 3x:
$$f'(x) = e^{3x} \cdot 3 = 3e^{3x}$$
✅ Answer: \( 3e^{3x} \)
📌 Integration
9. Find \( \int (4x^3 – 2x + 5)\,dx \)
👉 Show Answer
Apply the power rule for integrals to each term:
$$x^4 – x^2 + 5x + C$$
✅ Answer: \( x^4 – x^2 + 5x + C \)
10. Evaluate \( \int_0^2 (3x^2 + 1)\,dx \)
👉 Show Answer
First find the antiderivative:
$$F(x) = x^3 + x$$
Then apply the Fundamental Theorem of Calculus:
$$F(2) – F(0) = (8 + 2) – (0 + 0) = 10$$
✅ Answer: 10
11. Find \( \int 6x^2(x^3 + 1)^4\,dx \)
👉 Show Answer
Use U-Substitution. Let \( u = x^3 + 1 \), then \( du = 3x^2\,dx \)
Rewrite: \( 6x^2\,dx = 2\,du \)
$$\int 2u^4\,du = \frac{2u^5}{5} + C = \frac{2(x^3+1)^5}{5} + C$$
✅ Answer: \( \frac{2(x^3+1)^5}{5} + C \)
12. Find \( \int \sin(5x)\,dx \)
👉 Show Answer
Use U-Substitution. Let \( u = 5x \), then \( du = 5\,dx \), so \( dx = \frac{du}{5} \)
$$\int \sin(u) \cdot \frac{du}{5} = -\frac{\cos(u)}{5} + C = -\frac{\cos(5x)}{5} + C$$
✅ Answer: \( -\frac{\cos(5x)}{5} + C \)
🔥 Need More Practice?
If you want to really lock in these concepts before your exam, we put together a dedicated practice problem set for every single topic covered in this guide.
Each section has 10 extra problems with full step-by-step solutions — perfect for drilling the areas where you feel weakest.
- ✅ Extra Limit Problems
- ✅ Extra Derivative Problems
- ✅ Extra Integration Problems
- ✅ Full worked solutions for every problem
Final Thoughts
You’ve got everything you need right here. Calculus 1 is tough, but it’s absolutely learnable — and with focused practice, you can walk into that exam feeling confident.
Quick recap:
- Master limits first — they’re the foundation
- Know your derivative rules cold
- Practice integration daily
- Show ALL your work on the exam
- Sleep the night before — seriously
Good luck! You’ve got this. 🎓
Found this helpful? Share it with a classmate who needs it — and drop a comment below if you have questions!



