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Cos^2a=cos^2a-sin^2a for all values of a.

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1 vote

Answer:

its true besties

Explanation:

just got it correct on apx

User Ishaq Khan
by
7.9k points
3 votes

Explanation:


cos2a=cos^2a-sin^2a

Lets derive this equation,

we can write ,


cos2a= cos(a+a)

going by the identity,


cos(a+b)= cosa cosb - sina sinb

using the identity ,


cos(a+a)= cosacosa-sinasina .................(1)

After simplification of equation no.1 we get -


cos(2a)=cos^2a-sin^2a ............... (for any value of a)

Hence the equation is proved for every value of a.

User Daniszw
by
8.6k points

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