Math, asked by manisha73274, 11 months ago

pls help me to solve this​

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Anonymous: Mark my Ans as brainlist if it helps you:))

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Answered by rishu6845
1

Answer:

give me best ans and thanks plzzzzz

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manisha73274: thankyou so much rishu
manisha73274: kya aap ek or question me help kroge
rishu6845: btao
Answered by Anonymous
1

HEYA \:  \\  \\ GIVEN \:  \: QUESTION \:  \: Is \:  \\   \\   \frac{ \cos {}^{3} (x) -  \sin {}^{3} (x)  }{ \cos(x)  -  \sin(x) }   =  \frac{1}{2}  \frac{(2 +  \sin(2x)) }{}  \\  \\  \\ lhs \\  \\  \frac{ \cos {}^{3} (x) -  \sin {}^{3} (x)  }{ \cos(x)  -  \sin(x) }  \\  \\  \frac{( \cos(x) -  \sin(x)  ) {}^{3}   + 3 \sin(x) \cos(x)( \cos(x)  -  \sin(x) )  }{ \cos(x)  -  \sin(x) }  \\  \\  \\  \frac{( \cos(x) -  \sin(x) ) }{( \cos(x)  -  \sin(x) )}  \times  \frac{( \cos(x) -  \sin(x)) {}^{2}  + 3 \sin(x)  \cos(x)  }{1}  \\  \\  \\  \cos {}^{2} (x)  +  \sin {}^{2} (x)  - 2 \sin(x) \cos(x)  + 3 \sin(x)  \cos(x)  \\  \\  \\ 1 +  \sin(x)  \cos(x)  \\  \\  \\ 1 +  \frac{1}{2}  \frac{2 \sin(x)  \cos(x) }{}  \\  \\ 1 +  \frac{1}{2}  \sin(2x)  \\  \\  \frac{2 +  \sin(2x) }{2}  \\  \\ \\   =  \frac{1}{2} (2 +  \sin(2x) ) \:  \:  \: hence \:  \: proved \:  \:  \\  \\  \\ NOTE \:  \:  \:  \:  \\  \\ 1) \:  \: \:  a {}^{3}  - b {}^{3}  = (a - b) {}^{3}  + 3ab(a - b) \\  \\ 2) \:  \:  \:  \sin(2x)  = 2 \sin(x)  \cos(x)

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