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\(sin12°×cos18°×sec78°×cosec72°\) এর মান 1

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\(sin12°cos18°sec78°cosec72°\)
\(=sin12°cos18°sec(90°-12°) cosec(90°-18°)\)
\(=sin12°cos18°cosec12°sec18°\)
\(=sin12°cos18°\times \cfrac{1}{sin12°}\times \cfrac{1}{cos18°}\)
\(=1\)