सिद्ध कीजिए कि
` (cos 11^(@)+sin 11^(@))/(cos11^(@)-sin11^(@))= cot 34^(@)`

Explanation

` L.H.S = (cos 11^(@) + sin11^(@))/(cos11^(@) - sin 11^(@))`
` = (1+ tan 11^(@))/(1-tan 11^(@))`
` ( cos 11^(@) ` से अंश और हर को भाग देने पर)
` = (tan45^(@) + tan 11^(@))/(1-tan 45^(@)tan 11^(@))`
` = tan ( 45^(@) +11^(@))`
` = tan 56^(@) = tan (90^(@) - 34^(@))`
` = cot 34^(@) = R.H.S`