QCE Together Year 12 Specialist Maths: Double Angle Formulae for Sine and Cosine

#### Specialist Maths

Back to other subjects

# Double Angle Formulae for Sine and Cosine

This is part of the QCE Specialist Maths course. In this post, we learn to prove and solve double angle formulae for sine and cosine.

Here are the formulae:

##### Sine
sin(2x) = 2 sin(x) cos(x)
##### Cosine
cos(2x) = cos^2(x) -sin^2(x)  cos(2x) = 1 -2sin^2(x)  cos(2x) = 2cos^2(x) -1
##### Tangent
tan(2x) = \frac{2tan(x)}{1-tan^2(x)}

### 45,861 students have a head start...

Get exclusive QCE content & advice from our team of experts delivered weekly to your inbox!

## Here’s how we help...

### Holistic K-12 Tutoring

Attend our master-class workshops on how to ace your essays, assessments and exams!

### Comprehensive Workshops

Attend our master-class workshops on how to ace your essays, assessments and exams!

### Study, Uni, Career Mentoring

Attend our master-class workshops on how to ace your essays, assessments and exams!

### Senior School Workshops

Attend our master-class workshops on how to ace your essays, assessments and exams!

## 45,861 students have a head start...

Get exclusive study content & advice from our team of experts delivered weekly to your inbox!