# Trigonometry

## Sin 3A Formula – Proof and Examples

Here you will learn what is the formula of sin 3A with proof and examples based on it. Let’s begin – Sin 3A Formula The formula of sin 3A is $$3 sin A – 4 sin^3 A$$. Proof : We have, sin (A + B) = sin A cos B + cos A sin B …

## What is the Formula of Cos(A + B) ?

In this post you will learn what is the formula for cos (A + B) with examples. Cos (A + B) Formula : The formula of cos(A + B) is cos A cos B – sin A sin B. Example : If sin A = $$3\over 5$$ and cos B = $$9\over 41$$, find the …

## What is the Formula of Sin(A – B) ?

In this post you will learn what is the formula for sin (A – B) with examples. Sin (A – B) Formula : The formula of sin(A – B) is sin A cos B – cos A sin B. Example : If sin A = $$3\over 5$$ and cos B = $$9\over 41$$, find the …

## What is the Formula of Sin(A + B) ?

In this post you will learn what is the formula for sin (A + B) with examples. Sin (A + B) Formula : The formula of sin(A + B) is sin A cos B + cos A sin B. Example : If sin A = $$3\over 5$$ and cos B = $$9\over 41$$, find the …