Question

cos(x) + cos(π-x) =
​

Answer 1

$\textbf{To find:}$

$\textsf{The value of}$

$\mathsf{cosx+cos(\pi-x)}$

$\textbf{Solution:}$

$\mathsf{Consider,}$

$\mathsf{cosx+cos(\pi-x)}$

$\mathsf{Using,}$

$\boxed{\mathsf{cos(A-B)=cosA\,cosB+sinA\,sinB}}$

$\mathsf{=cosx+[cos\pi\,cosx+sin\pi\,sinx]}$

$\mathsf{=cosx+[(-1)cosx+(0)sinx]}$

$\mathsf{=cosx-cosx+0}$

$\mathsf{=0}$

$\implies\boxed{\mathsf{cosx+cos(\pi-x)=0}}$

$\textbf{Find more:}$

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