How can we say:(adsbygoogle = window.adsbygoogle || []).push({});

f(x)=A'sin(kx)+B'cos(kx)

or equivalently

f(x)=Ae[itex]^{ikx}[/itex]+Be[itex]^{-ikx}[/itex]??

How are these two equivalent knowing that e[itex]^{ix}[/itex]=cosx+isinx

I don't get this?

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# Some trigonometric, exponential thing?

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