Math, asked by raman9547, 1 year ago

cos4x+cos3x+cos2x/sin4x+sin3x+sin2x=cot3x

Answers

Answered by Anonymous
21
hope this helps you☺️☺️
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Answered by Swarnimkumar22
18

\bold{\huge{\underline{Solution-}}}

LHS=

 \displaystyle \sf \: { \frac{cos4x + cos3x + cos2x}{sin4x + sin3x + sin2x} }

 =  \displaystyle \sf \: { \frac{cos3x +  \left( \: cos4x + cos2x \right)}{sin3x +  \left( sin4x + sin2x\right)} }  \\  \\  =   \displaystyle \sf  \frac{cos3x + 2cos \left( \frac{4x + 2x}{2} \right)cos \left( \frac{4x - 2x}{2}  \right)}{sin3x + 2sin \left(  \frac{4x + 2x}{2} \right)cos \left( \frac{4x - 2x}{2}  \right)}  \\  \\  =  \displaystyle \sf \:  \frac{cos3x + 2cos3x \: cosx}{sin3x + 2sin3x \: cosx}  \\  \\  =  \displaystyle \sf \:  \frac{cos3x(1 + 2cosx)}{sin3x(1 + 2cosx)}  \\  \\  =  \displaystyle \sf \:  \frac{cos3x}{sin3x}  \\  \\  =  \displaystyle \sf \: cot3x

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