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Prove that cos^(2)(pi/8-A/2)-cos^(2)(pi/...

Prove that `cos^(2)(pi/8-A/2)-cos^(2)(pi/8+A/2)`
`[1-sin^(2)(pi/8-A/2)]-[1-sin^(2)(pi/8+A/2)]`
`=sin^(2)(pi/8+A/2)-sin^(2)(pi/8-A/2)`
`=sin{(pi/8+A/2)+(pi/8-A/2)} sin{(pi/8+A/2)-(pi/8-A/2)}`
`s=sinpi/4. sinA=1/sqrt(2)sinA`=RHS Hence Proved.

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