Finance Simple Interest
1. Let's start with **Simple Interest**. The problem is to find the interest earned on a principal amount over time.
2. The formula for simple interest is:
$$I = P \times r \times t$$
where $I$ is the interest, $P$ is the principal, $r$ is the annual interest rate (in decimal), and $t$ is the time in years.
3. For example, if you invest 1000 at 5% for 3 years, the interest is:
$$I = 1000 \times 0.05 \times 3 = 150$$
4. Next, **Compound Interest** involves interest on interest. The formula is:
$$A = P \left(1 + \frac{r}{n}\right)^{nt}$$
where $A$ is the amount, $n$ is the number of compounding periods per year.
5. For monthly compounding ($n=12$), 5% rate, 3 years, and 1000 principal:
$$A = 1000 \left(1 + \frac{0.05}{12}\right)^{12 \times 3}$$
Calculate the exponent and simplify to find $A$.
6. Moving to **Quadratic Functions**, the general form is:
$$y = ax^2 + bx + c$$
7. To expand and factorize quadratics, use methods like:
- Factoring by grouping
- Using the quadratic formula
- Completing the square
8. For example, factorize $x^2 + 5x + 6$:
$$x^2 + 5x + 6 = (x + 2)(x + 3)$$
9. The vertex of a parabola $y = ax^2 + bx + c$ is at:
$$x = -\frac{b}{2a}$$
Substitute back to find $y$.
10. The axis of symmetry is the vertical line $x = -\frac{b}{2a}$.
11. Intercepts are found by setting $y=0$ (roots) and $x=0$ (y-intercept).
12. Transformations include shifting (adding constants), reflecting (changing signs), and dilating (multiplying by constants).
13. For **Polynomials**, identify degree and leading coefficient to understand shape.
14. **Exponential functions** have the form:
$$y = a^x$$
with transformations shifting or scaling the graph.
15. **Circle graphs** represent data proportions; no formulas here.
16. **Reciprocal functions** are of form:
$$y = \frac{1}{x}$$
and their graphs are hyperbolas with transformations shifting or reflecting.
17. In **Non-Right Trigonometry**, use the unit circle to find exact values of sine, cosine, and tangent.
18. Convert degrees to radians by:
$$\text{radians} = \text{degrees} \times \frac{\pi}{180}$$
19. Solve trigonometric equations by finding all solutions in the domain.
20. The **Area Rule** for triangles is:
$$\text{Area} = \frac{1}{2}ab\sin C$$
21. The **Sine Rule** is:
$$\frac{a}{\sin A} = \frac{b}{\sin B} = \frac{c}{\sin C}$$
22. The **Cosine Rule** is:
$$c^2 = a^2 + b^2 - 2ab \cos C$$
23. Graph basic sine and cosine functions by plotting key points and noting amplitude and period.
24. In **Probability**, two-step experiments can be analyzed with tree diagrams, Venn diagrams, or two-way tables.
25. Conditional probability is:
$$P(A|B) = \frac{P(A \cap B)}{P(B)}$$
26. Independent events satisfy:
$$P(A \cap B) = P(A) \times P(B)$$
27. Set notation includes union ($\cup$), intersection ($\cap$), and complements.
28. For **Measurement**, surface area and volume formulas for prisms, cylinders, pyramids, and cones are:
- Prism surface area: sum of all faces
- Cylinder surface area: $2\pi r(h + r)$
- Pyramid surface area: base area + lateral area
- Cone surface area: $\pi r(l + r)$ where $l$ is slant height
29. Volume formulas:
- Prism: base area $\times$ height
- Cylinder: $\pi r^2 h$
- Pyramid: $\frac{1}{3}$ base area $\times$ height
- Cone: $\frac{1}{3} \pi r^2 h$
This overview covers the key formulas and concepts for your revision topics.