First question
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https://www.meritnation.com/ask-answer/question/if-sin-a-cos-a-m-then-prove-that-sin6a-cos6a-is-equal-to/trigonometry/10286999
https://www.meritnation.com/ask-answer/question/if-sin-a-cos-a-m-then-prove-that-sin6a-cos6a-is-equal-to/trigonometry/10286999