Subtraction Formulas
With trigonometry values, and subtraction formulas it is going to be easy to solve the complicated expression or finding an exact value. When the difference of two angles are needed, then subtraction formula can be used for the exact values.
The Sin subtraction formula of trigonometry is given as:
sin(A − B) = sin A cos B − cos A sin B
Cos Subtracting formula:
cos(A − B) = cos A cos B + sin A sin B
Tan Subtracting formula:
tan(A − B) = (tan A − tan B) / (1 + tan A tan B)
Solved example
Question: What is the value of cos 30
Solution:
Given,
Cos 30
As we already know the value of 60
= 0.866
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