If `(tan3A)/(tanA)=k(k!=1)` then which of the following is not true? (a)`(cosA)/(cos3A)=(k-1)/2` (b) `(sin3A)/(sinA)=(2k)/(k-1)` (c)`(cot3A)/(cotA)=1/k` (d) none of these

Explanation

To solve the problem, we start with the given equation:

\[ \frac{\tan 3A}{\tan A} = k \quad (k \neq 1) \]

Using the definition of tangent, we can rewrite the equation as:

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