two extremely difficult limit problems

fankafoon

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Nov 20, 2015
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1) lim x->infinity ((3^x+4^x)/4)^(1/x)
2) lim x->infinity x^(3/2)((x+1)^(1/2)+(x-1)^(1/2)-2x^(1/2))

Please help me out...
 
\(\displaystyle \mbox{1) }\, \)limx(3x+4x4)1x\displaystyle \displaystyle \lim_{x\, \rightarrow\, \infty}\, \left(\dfrac{3^x\, +\, 4^x}{4}\right)^{\dfrac{1}{x}}

\(\displaystyle \mbox{2) }\,\)limx(x32)((x+1)12+(x1)122x12)\displaystyle \displaystyle \lim_{x\, \rightarrow\, \infty}\, \left(x^{\frac{3}{2}}\right)\, \left((x\, +\, 1)^{\frac{1}{2}}\, +\, (x\, -\, 1)^{\frac{1}{2}}\, -\, 2x^{\frac{1}{2}}\right)
What are your thoughts? What methods have they given you? What have you tried? How far did you get? Where are you stuck?

Please be complete. Thank you! ;)
 
1) lim x->infinity ((3^x+4^x)/4)^(1/x)
2) lim x->infinity x^(3/2)((x+1)^(1/2)+(x-1)^(1/2)-2x^(1/2))
There are two useful theorems to use here:
If 0<c\displaystyle 0<c then (cn)1.\displaystyle (\sqrt[n]c)\to 1.
If 0<c<d\displaystyle 0<c<d then (cn+dnn)d\displaystyle (\sqrt[n]{c^n+d^n})\to d.
 
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