Question

Studiati monotonia șirurilor

Va rog ajutatima!!!

Answer 1

an+1/an=2^(n+1)/2^n=2*2^n/2^n=2>1
an+1/an>1=> an+1>an sir   crescator
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bn+1-bn=3/(n+1)-3/n=[3n-(3n+1)]/n*(n+1)=-1/n*(n+1)<0
bn+1-bn<0 bn+1<bn sir   monoton  des crescator
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dn=n²
dn+1=(n+1)²
dn+1-dn=(n+1)²-n²=n²+2n+1-n²=2n+1>0
dn+1-dn>0=>
dn+1>dn    sir   monoton crescator