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d-dx-ln-x-1-




Question Number 26947 by prakash jain last updated on 31/Dec/17
(d/dx)ln (Γ(x+1))=?
$$\frac{{d}}{{dx}}\mathrm{ln}\:\left(\Gamma\left({x}+\mathrm{1}\right)\right)=? \\ $$
Commented by abdo imad last updated on 31/Dec/17
we know that Γ(x+1)=x Γ(x) with x>0  ⇒ln(Γ(x+1)) =  lnx +ln(Γ(x))  ⇒(d/dx)ln(Γ(x+1))= (1/x)+ ((Γ^, (x))/(Γ(x))) .
$${we}\:{know}\:{that}\:\Gamma\left({x}+\mathrm{1}\right)={x}\:\Gamma\left({x}\right)\:{with}\:{x}>\mathrm{0} \\ $$$$\Rightarrow{ln}\left(\Gamma\left({x}+\mathrm{1}\right)\right)\:=\:\:{lnx}\:+{ln}\left(\Gamma\left({x}\right)\right) \\ $$$$\Rightarrow\frac{{d}}{{dx}}{ln}\left(\Gamma\left({x}+\mathrm{1}\right)\right)=\:\frac{\mathrm{1}}{{x}}+\:\frac{\Gamma^{,} \left({x}\right)}{\Gamma\left({x}\right)}\:. \\ $$
Answered by Femmy last updated on 31/Dec/17
ans  lnΓ+ln(x+1)  1/Γ+1/(x+1)
$$\mathrm{ans} \\ $$$$\mathrm{ln}\Gamma+\mathrm{ln}\left(\mathrm{x}+\mathrm{1}\right) \\ $$$$\mathrm{1}/\Gamma+\mathrm{1}/\left(\mathrm{x}+\mathrm{1}\right) \\ $$$$ \\ $$
Commented by prakash jain last updated on 31/Dec/17
Actually I meant Γ as gamma function
$$\mathrm{Actually}\:\mathrm{I}\:\mathrm{meant}\:\Gamma\:\mathrm{as}\:\mathrm{gamma}\:\mathrm{function} \\ $$
Commented by Femmy last updated on 31/Dec/17
okay sir
$$\mathrm{okay}\:\mathrm{sir} \\ $$$$ \\ $$

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