Question

(6a+7a) - (5a+ 9a+ a)

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Answer 1

Answer:

i) Let us consider the LHS sin3A+sin5A+sin7A+sin9Acos3A+cos5A+cos7A+cos9A On using the formulas, cos A + cos B = 2cos(A + B)/2 cos(A - B)/2 sin A

Answer 2

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(6a + 7a) - (5a + 9a + a)

=> 6a + 7a - 5a - 9a - a

=> 13a - 15a

=> (-2a)