Question

HEYA !!!

➡Please Solve Question No. 4 and 7 with Proper Explanation.

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Answer 1

Ans:4
Final Answer : 4 :
$\frac{ \sqrt{7} - 2 }{3}$

For Calculation see pic

Ans : 5

Formulas used :
1) cosC + cosD = 2 cos((C+D)/2 )cos(C-D) /2
Steps:
1) We will break it into different parts.

LHS =
$\frac{ \cos(6x) + 6 \cos(4x) + 15 \cos(2x) + 10 }{ \cos(5x) + 5 \cos(3x) + 10 \cos(x) }$
See Pic For Calculation