188k views
5 votes
Use the Chain Rule to find dz/dt. z = sin(x) cos(y), x = sqrt(t) , y = 4/t

User Wytze
by
7.2k points

1 Answer

3 votes

Final answer:

The student asked to find dz/dt using the Chain Rule for the function z = sin(x) cos(y), with x and y as functions of t. Calculus and Chain Rule are used to differentiate the given functions and find the time derivative of z.

Step-by-step explanation:

To find dz/dt using the Chain Rule for the function z = sin(x) cos(y), where x = sqrt(t) and y = 4/t, we will differentiate z with respect to x and y and then with respect to t.

The partial derivatives of z are:

  • dz/dx = cos(x) cos(y)
  • dz/dy = -sin(x) sin(y)

Then using the x(t) and y(t) given:

  • dx/dt = 1/(2 sqrt(t))
  • dy/dt = -4/t^2

Applying the Chain Rule to find dz/dt:

dz/dt = (dz/dx)(dx/dt) + (dz/dy)(dy/dt)

Substitute the partial derivatives and the derivatives of x and y with respect to t:

dz/dt = cos(x) cos(y)*(1/(2 sqrt(t))) - sin(x) sin(y)*(-4/t^2)

Finally, substitute x and y back into the equation to get dz/dt in terms of t.

User Bene
by
8.2k points