Question
Function
Find the first partial derivative with respect to σ
Find the first partial derivative with respect to r
∂σ∂p=r2
Evaluate
p=2×rσ
Multiply the terms
p=r2σ
Find the first partial derivative by treating the variable r as a constant and differentiating with respect to σ
∂σ∂p=∂σ∂(r2σ)
Use differentiation rule ∂x∂(g(x)f(x))=(g(x))2∂x∂(f(x))×g(x)−f(x)×∂x∂(g(x))
∂σ∂p=r2∂σ∂(2σ)r−2σ×∂σ∂(r)
Evaluate
More Steps

Evaluate
∂σ∂(2σ)
Use differentiation rule ∂x∂(cf(x))=c×∂x∂(f(x))
2×∂σ∂(σ)
Use ∂x∂xn=nxn−1 to find derivative
2×1
Multiply the terms
2
∂σ∂p=r22r−2σ×∂σ∂(r)
Use ∂x∂(c)=0 to find derivative
∂σ∂p=r22r−2σ×0
Any expression multiplied by 0 equals 0
∂σ∂p=r22r−0
Removing 0 doesn't change the value,so remove it from the expression
∂σ∂p=r22r
Solution
More Steps

Evaluate
r22r
Use the product rule aman=an−m to simplify the expression
r2−12
Reduce the fraction
r2
∂σ∂p=r2
Show Solution
Solve the equation
Solve for σ
Solve for p
Solve for r
σ=2pr
Evaluate
p=2×rσ
Multiply the terms
p=r2σ
Swap the sides of the equation
r2σ=p
Cross multiply
2σ=rp
Simplify the equation
2σ=pr
Divide both sides
22σ=2pr
Solution
σ=2pr
Show Solution