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Question -

sin2 24o –sin2 6o = (√5 – 1)/8



Answer -

Let us consider LHS:

sin2 24o – sin2 6o

we know, sin (A + B) sin (A – B) = sin2A –sin2B

Then the above equation becomes,

sin2 24o – sin2 6o =sin (24o + 6o) – sin (24o – 6o)

= sin 30o – sin 18o

= sin 30o – (√5 – 1)/4 [since, sin 18o =(√5 – 1)/4]

= 1/2 × (√5 – 1)/4

= (√5 – 1)/8

= RHS

Hence proved.

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