\(sin10θ=cos8θ\) এবং \(10θ\) ধনাত্মক সূক্ষ্মকোণ হলে, \(tan9θ\)-এর মান নির্ণয় করো । Madhyamik 2019


\(\sin 10\theta =\cos 8\theta\)
বা, \(\sin 10\theta = \sin(90^o-8\theta)\)
\(\therefore 10\theta = 90^o-8\theta\)
বা, \(18\theta =90^o\)
বা, \(\theta=5^o\)

\(\therefore \tan 9\theta= \tan (9\times 5^o)= \tan 45^o=1\) (Answer)

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