What is the slope of the curve x = cos(y) at the point where y=-pi/3

To find the slope of the curve x = cos(y) at the point where y = -π/3, we need to take the derivative of x with respect to y and evaluate it at that specific point.

To start, let's rewrite the equation x = cos(y) in terms of y as y = arccos(x). Taking the derivative of both sides with respect to y gives us:

1 = -sin(y) * (dy/dx)

Now, we need to find dy/dx. To do this, we can rearrange the equation to isolate dy/dx:

dy/dx = 1 / (-sin(y))

Substituting y = -π/3, we have:

dy/dx = 1 / (-sin(-π/3))

Next, we need to simplify the expression. Remember that sin(-θ) = -sin(θ):

dy/dx = 1 / (-sin(π/3))

Knowing that sin(π/3) = √3/2, we can simplify further:

dy/dx = 1 / (-√3/2)

To rationalize the denominator, we multiply the numerator and denominator by √3:

dy/dx = 1 / (-√3/2) * (√3/√3)

Simplifying this expression gives us:

dy/dx = -2/√3

Therefore, the slope of the curve x = cos(y) at the point where y = -π/3 is -2/√3.