Come risolvi (ln x) ^ 2 = ln x ^ 2 (lnx)2=lnx2?
Risposta:
x=1color(white)("XXX")orcolor(white)("XXX")x=e^2x=1XXXorXXXx=e2
Spiegazione:
Ricorda: ln(x^2)=2ln(x)ln(x2)=2ln(x)
lasciare k=ln(x)k=ln(x)
Quindi
color(white)("XXX")(ln(x))^2=ln(x^2)XXX(ln(x))2=ln(x2)
è equivalente
color(white)("XXX")k^2=2kXXXk2=2k
color(white)("XXX")k^2-2k=0XXXk2−2k=0
color(white)("XXX")k(k-2)=0XXXk(k−2)=0
color(white)("XXX"){: (k=0,color(white)("XX")orcolor(white)("XX"),k=2), (rarr ln(x)=0,,rarr ln(x)=2), (rarr e^0=x,,rarr e^2=x), (rarr x=1,,rarr x=e^2) :}