Compare the numbers X=(log2(√5+1))3 and Y=1+log2(√5+2).
First, note that 5>1, which gives 2√5>2 and further translates into 5+2√5+1=(√5+1)2>8, which implies √5+1>232, taking base 2 logarithm of both sides of the inequality we get:
log2(√5+1)>32
(log2(√5+1))3>(32)3=278
On the other hand, we have
52>√5
92=52+2>√5+2
∴log2(92)>log2(√5+2)
log29−1>log2(√5+2)
1+log29−1>1+log2(√5+2)
log29>1+log2(√5+2)
If we can prove 278>log29, then we can say X>Y.
Note that 227=(25)5+2>4(33)5>316=98, this suggest 278>log29 and we're hence done as we can conclude X>Y.
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