Question

prove that cos (π/3 +x) = 1/2 (cos x - √3 sin x)
please solve this urgent​

Answer 1

Question : To prove $\textsf{Cos }\frac{\pi }{3+x} = \frac{1}{2} \textsf{(cos x }\sqrt[3]{sin \:x})$

Solution:

We know that,

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

Substituting ,

$\textsf{cos}(\frac{\sqrt{\pi +x}}{3})=\frac{\sqrt{\pi }}{3}\textsf{cos x-sin}(\frac{\sqrt{\pi }}{3})\textsf{sin x}\\\\\textsf{A=}\pi \: \textsf{and B=x}\\\\\textsf{cos}(\frac{\pi}{3})+x=\textsf{cos x}-\frac{\sqrt{3}}{2}}\textsf{sin x}\\\\\textsf{cos}(\frac{\pi}{3})+x=\frac{1}{2}(\textsf{cos x} -\sqrt{3}\textsf{sin x})$

So

$\textsf{Cos }\frac{\pi }{3+x} = \frac{1}{2} \textsf{(cos x }\sqrt[3]{sin \:x}) \textsf{is not true.}$

Answer 2

Answer:

nope ( π/3+x≠1/2

umm am a bit lazy i solved it in my notebook

dirtily so i can't show you and i can't type it again so

죄송합니다

                                                             $JENNIE$

죄송합니다 :(