3The frequency (in Hz) of a vibrating violin string is given by f = 1 2L s T rho where L is the length of the string (in meters), T is the tension of the string (in Newtons), and rho is the linear density of the string. a) Find the derivative of f with respect to: i. L (assuming T and rho are constants) ii. T (assuming L and rho are constants) iii. rho (assuming L and T are constants)

Respuesta :

Answer:

(i) [tex]\dfrac{df}{dL}=-\dfrac{1}{2L^2}\sqrt{\dfrac{T}{\rho}}[/tex]

(ii) [tex]\dfrac{df}{dT}=\dfrac{1}{4L\sqrt{T\rho}}[/tex]

(iii) [tex]\dfrac{df}{d\rho}=-\dfrac{\sqrt{T}}{4L\rho^{-\frac{3}{2}}}}[/tex]

Step-by-step explanation:

Let as consider the frequency (in Hz) of a vibrating violin string is given by

[tex]f=\dfrac{1}{2L}\sqrt{\dfrac{T}{\rho}}[/tex]

(i)

Differentiate f with respect L (assuming T and rho are constants).

[tex]\dfrac{df}{dL}=\dfrac{d}{dL}\dfrac{1}{2L}\sqrt{\dfrac{T}{\rho}}[/tex]

Taking out constant terms.

[tex]\dfrac{df}{dL}=\dfrac{1}{2}\sqrt{\dfrac{T}{\rho}}\dfrac{d}{dL}\dfrac{1}{L}[/tex]

[tex]\dfrac{df}{dL}=\dfrac{1}{2}\sqrt{\dfrac{T}{\rho}}(-\dfrac{1}{L^2})[/tex]

[tex]\dfrac{df}{dL}=-\dfrac{1}{2L^2}\sqrt{\dfrac{T}{\rho}}[/tex]

(ii)

Differentiate f with respect T (assuming L and rho are constants).

[tex]\dfrac{df}{dT}=\dfrac{d}{dT}\dfrac{1}{2L}\sqrt{\dfrac{T}{\rho}}[/tex]

Taking out constant terms.

[tex]\dfrac{df}{dT}=\dfrac{1}{2L}\sqrt{\dfrac{1}{\rho}}\dfrac{d}{dT}\sqrt{T}}[/tex]

[tex]\dfrac{df}{dT}=\dfrac{1}{2L}\sqrt{\dfrac{1}{\rho}}(\dfrac{1}{2\sqrt{T}})[/tex]

[tex]\dfrac{df}{dT}=\dfrac{1}{4L\sqrt{T\rho}}[/tex]

(iii)

Differentiate f with respect rho (assuming L and T are constants).

[tex]\dfrac{df}{d\rho}=\dfrac{d}{d\rho}\dfrac{1}{2L}\sqrt{\dfrac{T}{\rho}}[/tex]

Taking out constant terms.

[tex]\dfrac{df}{d\rho}=\dfrac{\sqrt{T}}{2L}\dfrac{d}{d\rho}(\rho)^{-\frac{1}{2}}}[/tex]

[tex]\dfrac{df}{d\rho}=\dfrac{\sqrt{T}}{2L}(-\dfrac{1}{2}(\rho)^{-\frac{3}{2}}})[/tex]

[tex]\dfrac{df}{d\rho}=-\dfrac{\sqrt{T}}{4L\rho^{-\frac{3}{2}}}}[/tex]