**Contents**show

## What is sinA * sinB?

sina **sinb =** **1**. **2**(cos(a − b) − cos(a + b))

## What is sinA * cosB?

The identities

2 sinA cosB = **sin(A + B) + sin(A − B)** 2 cosA cosB = cos(A − B) + cos(A + B) 2 sin A sin B = cos(A − B) − cos(A + B)

## What is the formula of cosB?

Transformation of sum or difference into product

Transformation formulae | Key to remember |
---|---|

2sinA cosB = sin(A + B) + sin(A – B) | 2 sin. cos = sin + sin |

2 cosA sinB = sin(A + B) – sin(A – B) | 2 cos. sin = sin – sin |

2 cosA cosB = cos(A + B) + cos(A – B) | 2 cos. cos = cos + cos |

## What is the value of sin a B sin AB?

→ Sin(A+B) + Sin(A-B) = **2 sinA**.

## Is sin a B sin a sin B?

Answer Expert Verified

Therefore Sin(A+B) is not equal to SinA+SinB. Therefore **Sin(A+B) = SinA+SinB** when either A is 0° or B is 0°.

## What is the formula of sin a sin B sin C?

sin A + sin B – **sin C = 4sin(A/2)sin(B/2)cos (C/2)** .

## Is cos a cos b same as cos a B?

Cos a Cos b is the trigonometry identity for two different angles whose sum and difference are known. The cos a cos b identity is half the sum of the cosines of the sum and difference of the angles a and b, that is, **cos a cos b = (1/2)[cos**(a + b) + cos(a – b)].

## How do you find the value of tan15?

**Value of Tan 15**

- Tan (15°) can be found if we know the value of sin 15 degrees and cos 15 degrees. …
- From the above table, we have the values of tan, sin and cos ratios for 0°, 30°, 45°, 60° and 90°. …
- tan (15°) = √3 – 1/ √3 + 1.
- Hence, the value of tan (15°) is √3 – 1/√3 + 1.
- ∴ Tan (15°) = (1.732 – 1)/(1.732 + 1) = 0.2679.