User:Drummondjacob

Compound Angle Formulae
$$\sin (x + y) = \sin (x) \times \cos (y) + \cos (x) \times \sin (y)\,\!$$

$$\sin (x - y) = \sin (x) \times \cos (y) - \cos (x) \times \sin (y)\,\!$$

$$\cos (x + y) = \cos (x) \times \cos (y) - \sin (x) \times \sin (y)\,\!$$

$$\cos (x - y) = \cos (x) \times \cos (y) + \sin (x) \times \sin (y)\,\!$$

$$\tan (x + y) = \frac { \tan (x) + \tan (y)} {1 - \tan (x) \times \tan (y)}$$

$$\tan (x - y) = \frac { \tan (x) - \tan (y)} {1 - \tan (x) \times \tan (y)}$$

$$\cot (x + y) = \frac { \cot(x) \times \cot (y) - 1} { \cot (x) + \cot (y)}$$

$$\cot (x - y) = \frac { \cot(x) \times \cot (y) + 1} { \cot (y) - \cot (x)}$$

Original
$$A = P \left( r+ \frac{r}{(1+r)^n-1} \right) $$

Attempt 2: Work in progress
$$A = P \left( r+ \frac{r}{(1+r)^n-1} \right) $$

$$r+ \frac{r}{(1+r)^n-1} = \frac{P}{A} $$

$$\frac{r}{(1+r)^n-1} = \frac{P}{A} - r $$

Attempt 1: Failure
$$A = Pr \left(1+ \frac{1}{(1+r)^n-1}\right) $$

$$\frac{A}{Pr} = 1+ \frac{1}{(1+r)^n-1} $$