# Numbers | Maths with Lemon

Source: https://mathswithlemon.io/aa-functions-trigonometric-functions.html


## Trigonometric Functions

"You cannot say, “I will look it up.” Your birthday and social security number are things you look up; trigonometric functions and identities are what you know all the time. " Ramamurti Shankar


#### Trigonometric Functions


##### What you have to know:

- You must know the basic properties of sinx, cosx and tanx (If not, check this lesson)
- You must be able to solve trigonometric equations (If not, check this lesson)
- The trigonometric identity (If not, check this lesson)

##### Key Points

- 1. Watch the video:
- 2. Check out this presentation

#### IB solved questions on Trigonometric functions


##### What you have to know:

- You must be able to manipulate algebraic equations.

##### Key Points

- 1. Watch the video:
- 4. Check out this presentation

#### Extra


##### Material and references:

- Hodder Book SL(ISBN: 9781510462359) : 18B, 18C, 18D

##### Key Points

- sine rule (ambiguous case): \( \theta \) or \( 180^\circ-\theta \) Pythagorean identity: \( \cos^2\theta+\sin^2\theta=1 \) double angle: \( \sin 2\theta = 2\sin\theta\cos\theta \) \( \cos 2\theta = \cos^2\theta-\sin^2\theta \) \( \cos 2\theta = 2\cos^2\theta-1 \) \( \cos 2\theta = 1-2\sin^2\theta \) trig graphs: sketch \( \sin x,\ \cos x,\ \tan x \) transformations: \( a\sin(b(x+c))+d \), \( a\cos(b(x+c))+d \) amplitude \( = a \) period \( = \dfrac{2\pi}{b} \)

### IB Past Paper Problems

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