If the sides of a triangle are 3,5 and 7, then find cos A

Explanation

To find \( \cos A \) for a triangle with sides 3, 5, and 7, we can use the cosine rule. The cosine rule states:

\[ \cos A = \frac{b^2 + c^2 - a^2}{2bc} \]

where \( a \), \( b \), and \( c \) are the lengths of the sides opposite to angles \( A \), \( B \), and \( C \) respectively.

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