Nth Derivative of xnyn Using Leibniz Theorem
In this problem, we evaluate the nth derivative of xnyn using the Leibniz Theorem. This method is commonly applied to higher-order derivatives involving products of functions.
Problem
Find the nth derivative of y = xn · yn using Leibniz theorem.
Solution
Leibniz Theorem
dn/dxn(uv)
= Σ C(n, r) · dru/dxr · dn−rv/dxn−r,
where r = 0 to n
where r = 0 to n
Step 1: Choose Functions
u = xn
v = yn
v = yn
Step 2: Derivatives of Each Function
Derivative of u = xn:
dr/dxr(xn)
= n(n−1)(n−2)…(n−r+1)xn−r
Derivative of v = yn:
dn−r/dxn−r(yn)
= n(n−1)(n−2)…(r+1)yr
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Step 3: Apply Leibniz Theorem
dn/dxn(xnyn)
= Σ C(n, r) ·
[n(n−1)…(n−r+1)xn−r] ·
[n(n−1)…(r+1)yr]
This is the required general expression.