\(4.\left(-\frac{1}{2}\right)^3-3.\left(-\frac{1}{2}\right)^2-3.\left(-\frac{1}{2}\right)^1=4.-\frac{1}{8}-3.\frac{1}{4}-3.-\frac{1}{2}\)
\(=-\frac{1}{2}-\frac{3}{4}-\left(-\frac{3}{2}\right)\)
\(=-\frac{1}{2}-\frac{3}{4}+\frac{3}{2}\)
\(=\left(-\frac{1}{2}+\frac{3}{2}\right)-\frac{3}{4}\)
\(=1-\frac{3}{4}\)
\(=\frac{1}{4}\)
Hok tốt nha^^
4*(-1/2) mu 3 -2*(-1/2) mu 2-3*(-1/2) mu 1
chung minh 1-1/2 mu 2 -1/ 3 mu 2 - 1/ 4 mu 2 - ... - 1/2015 mu 2 > 1/2015
c/m 1/2mu 3 +1/3 mu 3 +..................+1/ 2006 mu 3<1/4
c/m 1/2 mu 3 +1/3 mu 3 +..................+1/2006 mu3 >1/15
Cho A=1/2+(1/2) mu 2 +(1/2) mu 3 + (1/4) mu 4 +........(1/2) mu 98 +(1/2) mu 99
C/m A <1
Cho S =1/5+2/5 mu 2 +3/5mu 3 +4/5 mu 4+....+2012/5 mu 2012
So sánh S với 1/3
9 * 3 mu 3 * 1 phan 81 * 3 mu 2
4.2mu5 / {2 mu 3. 1 phan 16 }
Cho S=1/5+2/5 mu 2+3/5 mu 3+...+2012/5 mu 2012
So sánh S với 1/3
Cm 1/2 mu 2 - 1/ 2mu 4 + 1/ 2 mu 6-...-1/2mu 4n -2 -1/2 mu 4n + ...+ 1/ 2 mu 2014 - 1/ 2 mu 2016 < 0,2
