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प्रश्न
Using tables evaluate the following :
`cos^2 0 + cos^2 pi/6 + cos^2 pi/3 + cos^2 pi/2`
उत्तर
We know that,
cos 0 = 1, cos `pi/6 = sqrt(3)/2, cos pi/3 = 1/2`,
`cos pi/2` = 0
`cos^2 0 + cos^2 pi/6 + cos^2 pi/3 + cos^2 pi/2`
= `1 + (sqrt(3)/2)^2 + (1/2)^2 + 0`
= `1 + 3/4 + 1/4`
= 2
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