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sin ^2 5^@ + sin ^2 10^@ + sin ^2 1...

` sin ^2 5^@ + sin ^2 10^@ + sin ^2 15 ^2 + …….. + sin^2 90^2 =`

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LHS
`=sin^2 5+sin^2 10+sin^2 15+...+sin^2 50`
`=(sinn^2 5+cos^2 5)+(sin^2 10+cos^2 10)+...+1/2+1`
`=(1+1+1+1+1+1+1+1+1)+1/2+1`
`=9+1/2=19/2`
RHS.
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