Problem

Find an equation for the tangent plane to the surface
\[
z+5=x y^{3} \cos (z)
\]
at the point $(5,1,0)$.

Answer

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Answer

So, the equation of the tangent plane to the surface \(z+5=xy^3\cos(z)\) at the point \((5,1,0)\) is \(\boxed{x + 15y - z - 20 = 0}\).

Steps

Step 1 :Given the surface equation \(z+5=xy^3\cos(z)\), we want to find the equation of the tangent plane at the point \((5,1,0)\).

Step 2 :The equation of the tangent plane to a surface given by \(f(x, y, z) = 0\) at a point \((x_0, y_0, z_0)\) is given by \(f_x(x_0, y_0, z_0)(x - x_0) + f_y(x_0, y_0, z_0)(y - y_0) + f_z(x_0, y_0, z_0)(z - z_0) = 0\), where \(f_x\), \(f_y\), and \(f_z\) are the partial derivatives of \(f\) with respect to \(x\), \(y\), and \(z\), respectively.

Step 3 :First, we need to find the partial derivatives of the function \(f(x, y, z) = xy^3\cos(z) + 5 - z\).

Step 4 :The partial derivative of \(f\) with respect to \(x\) is \(y^3\cos(z)\), with respect to \(y\) is \(3xy^2\cos(z)\), and with respect to \(z\) is \(-xy^3\sin(z) - 1\).

Step 5 :Substituting the point \((5,1,0)\) into the partial derivatives, we get \(f_x = 1\), \(f_y = 15\), and \(f_z = -1\).

Step 6 :Substituting these values into the equation of the tangent plane, we get the final equation \(x + 15y - z - 20 = 0\).

Step 7 :So, the equation of the tangent plane to the surface \(z+5=xy^3\cos(z)\) at the point \((5,1,0)\) is \(\boxed{x + 15y - z - 20 = 0}\).

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