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Question Number 121720 by Jamshidbek2311 last updated on 11/Nov/20

Does this example work that way.  f(x)=x^x    f′(x)=x^x ∙(lnx+1)

$${Does}\:{this}\:{example}\:{work}\:{that}\:{way}. \\ $$$${f}\left({x}\right)={x}^{{x}} \:\:\:{f}'\left({x}\right)={x}^{{x}} \centerdot\left({lnx}+\mathrm{1}\right) \\ $$

Answered by Dwaipayan Shikari last updated on 11/Nov/20

f(x)=x^x   log(f(x))=xlogx  ((f′(x))/(f(x)))=1+logx  f′(x)=f(x)(1+logx)=x^x (1+logx)

$${f}\left({x}\right)={x}^{{x}} \\ $$$${log}\left({f}\left({x}\right)\right)={xlogx} \\ $$$$\frac{{f}'\left({x}\right)}{{f}\left({x}\right)}=\mathrm{1}+{logx} \\ $$$${f}'\left({x}\right)={f}\left({x}\right)\left(\mathrm{1}+{logx}\right)={x}^{{x}} \left(\mathrm{1}+{logx}\right) \\ $$

Answered by ebi last updated on 11/Nov/20

  Yes.  f(x)=x^x   let y=x^x   ln y=ln x^x   ln y=x ln x  (d/dx)(ln y)=(d/dx)(x ln x)  (1/y)∙(dy/dx)=x∙(1/x)+ln x  (1/y)∙(dy/dx)=1+ln x  (dy/dx)=y(1+ln x)  ∴f′(x)=x^x (1+ln x)

$$ \\ $$$${Yes}. \\ $$$${f}\left({x}\right)={x}^{{x}} \\ $$$${let}\:{y}={x}^{{x}} \\ $$$${ln}\:{y}={ln}\:{x}^{{x}} \\ $$$${ln}\:{y}={x}\:{ln}\:{x} \\ $$$$\frac{{d}}{{dx}}\left({ln}\:{y}\right)=\frac{{d}}{{dx}}\left({x}\:{ln}\:{x}\right) \\ $$$$\frac{\mathrm{1}}{{y}}\centerdot\frac{{dy}}{{dx}}={x}\centerdot\frac{\mathrm{1}}{{x}}+{ln}\:{x} \\ $$$$\frac{\mathrm{1}}{{y}}\centerdot\frac{{dy}}{{dx}}=\mathrm{1}+{ln}\:{x} \\ $$$$\frac{{dy}}{{dx}}={y}\left(\mathrm{1}+{ln}\:{x}\right) \\ $$$$\therefore{f}'\left({x}\right)={x}^{{x}} \left(\mathrm{1}+{ln}\:{x}\right) \\ $$

Commented by Jamshidbek2311 last updated on 11/Nov/20

thank

$${thank} \\ $$

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