I'm trying to prove that
3−2√1−15m21+12m2≥1+3m2
I have obtained in a CAS software the Taylor expansion in m=0
One posibility to prove the inequality is showing coeficients in Taylor expansion are non-negative, by I don't find how.
Really I want only to obtain inequality. Some idea?
EDIT
m must be between $0
Answer
3−2√1−15m21+12m2≥1+3m2⟺
3−2√1−15m2≥(1+3m2)(1+12m2)⟺
2√1−15m2≤3−(1+3m2)(1+12m2)⟺
√1−15m2≤3−(1+3m2)(1+12m2)2⟺
√1−15m2≤2−15m2−36m42
Note that on the interval you're concerned about, the right hand side is always positive. Proof: it's obviously decreasing on (0,1√15), and is equal to 2150 at the right endpoint. Therefore squaring both sides is legal here with an ⟺ statement.
√1−15m2≤2−15m2−36m42⟺
1−15m2≤(2−15m2−36m42)2⟺
1−15m2≤324m8+270m6+814m4−15m2+1⟺
0≤324m8+270m6+814m4
This last statement is clearly true.
No comments:
Post a Comment