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MHT CET · Maths · Trigonometric Ratios & Identities

If \(\tan \theta+\cot \theta=4\), then \(\tan ^{4} \theta+\cot ^{4} \theta=\)

  1. A 194
  2. B 110
  3. C 80
  4. D 191
Verified Solution

Answer & Solution

Correct Answer

(A) 194

Step-by-step Solution

Detailed explanation

\(\tan \theta+\cot \theta=4\)
On squaring both side, we get
\(\tan ^{2} \theta+\cot ^{2} \theta+2 \tan \theta \cot \theta=16 \Rightarrow \tan ^{2} \theta+\cot ^{2} \theta=14\)
On squaring both side, we get
\(\begin{array}{l}
\tan ^{4} \theta+\cot ^{4} \theta+2 \tan ^{2} \theta \cot ^{2} \theta=196 \\
\tan ^{4} \theta+\cot ^{4} \theta=196-2=194
\end{array}\)