सिध्द कीजिए कि : ` ( cos theta + cos 2 theta + cos 3 theta + cos 4 theta)/( sin theta + sin 2 theta + sin 3 theta +sin 4 theta) = cot .(5 theta)/(2)`

Explanation

बायाँ पक्ष `= ((cos theta + cos 4 theta )+ (cos 2 theta +cos 3 theta))/((sin theta + sin 4 theta )+ (sin 2 theta + sin 3 theta))`
`(2 cos .(5 theta)/(2) cos .((-3 theta)/(2)) + 2 cos .(5 theta)/(2) cos .((-theta)/(2)))/(2 sin .(5 theta)/(2). cos .((-3 theta)/(2)) + 2 sin. (5 theta)/(2). cos .((- theta)/(2)))`
` = (2 cos .(5 theta)/(2).(cos .(3 theta)/(2) + cos .( theta)/(2)))/(2 sin .(5 theta)/(2) + (cos . (3 theta)/(2) + cos .( theta)/(2)))`
` = cot . (5 theta)/(2)=` दायाँ पक्ष।