darksky
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 Sep 24 awarded Autobiographer Aug 25 awarded Famous Question May 25 awarded Notable Question Feb 21 awarded Popular Question Sep 11 awarded Scholar Sep 11 accepted Sinusoidal Wave Displacement Function Sep 11 awarded Student Sep 11 comment Sinusoidal Wave Displacement Function We're going off topic. My question is a simple sine or cosine function. I'm not a physics expert. Sep 11 comment Sinusoidal Wave Displacement Function Well assume that the initial phase IS 0 and not "when its 0"...? Sep 11 comment Sinusoidal Wave Displacement Function Oh okay thanks now I understand. Well... at t = 0, when the initial phase is 0, would a sinusoidal wave still always be cosine, or would it still depend/vary on the conditions? Sep 11 comment Sinusoidal Wave Displacement Function ...which would be written as a cosine function (including the initial phase)? Or can I see the same function above you gave as a sine function, depending on the question? Sep 11 comment Sinusoidal Wave Displacement Function I am aware of the identity, but sin(x) and cos(x) on their own, are not equal. Therefore, sin(kx - wt) is not equal to cos(kx - wt). So when I'm given a question say: Write down the displacement function of a sinusoidal wave with A = 2.0, k = 4.0 and w = 1.5, would I write it as y(x,t) = 2.0cos(4x - 1.5t) or y(x,t) = 2.0sin(4x - 1.5t)? Forget about trig identities: I do not understand whether sinusoidal waves are ALWAYS cosine (as the book highlights a cosine function) or may be sine and differs per each function (which I should determine from a graph/given in the question) Sep 11 asked Sinusoidal Wave Displacement Function