[tex]if \: a+ b+c=180\:then\:Σ\frac{ \cot\:a + \: \cot \: b }{ \tan \: a + \tan \: b } = [/tex]
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[tex]if \: a+ b+c=180\:then\:Σ\frac{ \cot\:a + \: \cot \: b }{ \tan \: a + \tan \: b } = [/tex]
please answer this question
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Answer:
applying cos on both sides
cos (A+B+C)=cos(180)
cot A cotB cotC+cotB cotA-1/cotA+cotB+cotC-cotA cotB cotC =1/2
cot(A+B+C)=cot A cotB+cotC +cotB cotA-1/cotA+cotB+cotC-cotA cotB cotC
cotA+cotB+cotC- cotA cotB cotC=0
cotA+cotB+cotC=cotA cotB cotC
cotA+cotB+cotC/cotA cot B cot C=1