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TFM

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## Homework Statement

The instantaneous rate at which a wave transmits energy along a string (instantaneous power) is

[tex] P(x,t) = =F\frac{\partial y(x,t)}{\partial x} \frac{\partial y(x,t)}{\partial t}[/tex]

where F is the tension.

Show that for all values of x, the average power [tex]P_a_v[/tex] carried by the standing wave is zero. (Equation [tex] P_a_v = \frac{1}{2}\sqrt{\mu F} \omega^2 A^2[/tex] does not apply here. Can you see why?)

## Homework Equations

[tex] P(x,t) = -F sin(A_S_W(\omega t)kA_S_Wcos(kx))(A_S_Wsin(kx)\omega cos(\omega t)) [/tex]

^ Power equation calculated from part 1

## The Attempt at a Solution

The answer section is in the form of a writing box (I am using Mastering Physics), Not the normal maths box.

What is the best way to show for all values of x the power is zero?

TFM