समीकरण ` sin alpha + sin ( alpha + theta) + sin (alpha + 2 theta) =0` से `theta` का व्यापक मान ज्ञात कीजिए ।

Explanation

` sin (alpha + 2theta) + sin alpha + sin (alpha + 2theta )=0`
`rArr sin ( alpha + 2theta ) + si alpha + sin ( alpha + theta ) = 0 `
`rArr 2 sin ( alpha + theta ) * cos theta + sin ( alpha + theta ) =0`
` rArr sin (alpha + theta) = 0 "या " 2 cos theta + 1 = 0 `
अब ` sin ( alpha + theta) = 0 `
` rArr alpha + theta = npi`
` rArr theta = n pi - alpha `
और ` 2 cos theta + 1 = 0 `
` rArr cos theta = -1/2 `
` = - cos. pi/3 = cos (pi - pi/3)= cos. (2pi)/3 `
` rArr theta = 2npi pm (2pi)/3 `