Trigonometry

There’s these Function that are useful to know about.

sin⁡(θ),cos⁡(θ),tan⁡(θ)\sin(\theta), \cos(\theta), \tan(\theta)

Where θ\theta is the angle in radians.

1 radians is 180π\frac{180}{\pi} degrees. The radian to degree conversion is linear.

For the purpose of this course, we only need to think about trigonometry as functions. No need to mess around with triangles, but it sure will be helpful to know more about them.

Also know these fun facts

sin⁡(α±β)=sin⁡αcos⁡β±cos⁡αsin⁡β\sin(\alpha\pm \beta) = \sin\alpha\cos\beta \pm \cos\alpha\sin\beta cos⁡(α±β)=cos⁡αcos⁡β∓sin⁡αsin⁡β\cos(\alpha\pm \beta) = \cos\alpha\cos\beta \mp \sin\alpha\sin\beta tan⁡(α±β)=tan⁡α±tan⁡β1∓tan⁡αtan⁡β\tan(\alpha\pm \beta) = \frac{\tan\alpha \pm \tan\beta}{1 \mp \tan\alpha\tan\beta}

This is called the Pythagorean identity

sin⁡2(θ)+cos⁡2(θ)=1\sin^2(\theta) + \cos^2(\theta) = 1