Toolkit for Exercise 10.1 , What are Allied Angles ?

Lesson#1
Chapter 10
Trigonometric Identities
Toolkit for Exercise 10.1
Fundamental Law of Trigonometry
1) cos(−)=cos⁡ cos⁡+sin⁡ sin⁡
Math.Ex.10.1, Part1(10.1),
What are Allied Angles ?
Allied Angles: A group of angles is said to be allied if sum or difference of any two of them gives integral multiple of 90° /2.
How can we generate Allied Angles?
What is the use of the concept of Allied angles ?
The concept of allied angles is used to find trigonometric functional values of numerically large angles.
Drawback of the use of the concept of Coterminal Angles:
Trigonometric Identities
Chapter No 10
Exercise No 10.1
Mathematics
part 1