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The differentiable functions 
x and 
y are related by the following equation:

(1)/(y)=cos(x)
Also, 
(dx)/(dt)=-2.
Find 
(dy)/(dt) when 
x=pi.

The differentiable functions x x and y y are related by the following equation:\newline1y=cos(x) \frac{1}{y}=\cos (x) \newlineAlso, dxdt=2 \frac{d x}{d t}=-2 .\newlineFind dydt \frac{d y}{d t} when x=π x=\pi .

Full solution

Q. The differentiable functions x x and y y are related by the following equation:\newline1y=cos(x) \frac{1}{y}=\cos (x) \newlineAlso, dxdt=2 \frac{d x}{d t}=-2 .\newlineFind dydt \frac{d y}{d t} when x=π x=\pi .
  1. Differentiate with respect to tt: Differentiate both sides of the equation 1y=cos(x)\frac{1}{y} = \cos(x) with respect to tt using implicit differentiation.\newlineSince 1y\frac{1}{y} is y1y^{-1}, we use the chain rule to differentiate y1y^{-1} with respect to tt, which gives us y2dydt-y^{-2} \cdot \frac{dy}{dt} on the left side. On the right side, the derivative of cos(x)\cos(x) with respect to tt is 1y=cos(x)\frac{1}{y} = \cos(x)00.\newlineSo, we have 1y=cos(x)\frac{1}{y} = \cos(x)11.
  2. Substitute given value: Substitute the given value of (dx)/(dt)(dx)/(dt) into the equation.\newlineWe know that (dx)/(dt)=2(dx)/(dt) = -2, so we substitute this into the equation to get y2(dy)/(dt)=sin(x)(2)-y^{-2} * (dy)/(dt) = -\sin(x) * (-2).
  3. Evaluate sin(x)\sin(x): Evaluate sin(x)\sin(x) when x=πx = \pi.\newlineSince sin(π)=0\sin(\pi) = 0, we substitute this into the equation to get y2dydt=0(2)-y^{-2} \cdot \frac{dy}{dt} = -0 \cdot (-2).
  4. Simplify the equation: Simplify the equation.\newlineSince 0×(2)-0 \times (-2) is 00, the equation simplifies to y2×dydt=0-y^{-2} \times \frac{dy}{dt} = 0.
  5. Solve for (dydt):</b>Solvefor$(dydt)(\frac{dy}{dt}):</b> Solve for \$(\frac{dy}{dt}).\newlineTo find (dydt)(\frac{dy}{dt}), we divide both sides of the equation by y2-y^{-2}. However, since the right side of the equation is 00, (dydt)(\frac{dy}{dt}) must also be 00, regardless of the value of yy.\newlineSo, (dydt)=0(\frac{dy}{dt}) = 0.

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