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Easy.
Ta có: Nếu \(\frac{a}{b}>1\)thì \(\frac{a}{b}>\frac{a+m}{b+m}\left(m>0\right)\) (bạn tự c/m)
Mặt khác,ta có: \(C=\frac{2016^{99}+1}{2016^{89}+1}=\frac{2016\left(2016^{99}+1\right)}{2016\left(2016^{89}+1\right)}\)
\(=\frac{2016^{100}+2016}{2016^{90}+2016}=\frac{\left(2016^{100}+1\right)+2015}{\left(2016^{90}+1\right)+2015}\)
Mà \(\frac{\left(2016^{100}+1\right)+2015}{\left(2016^{90}+1\right)+2015}>1\)
Nên \(C=\frac{\left(2016^{100}+1\right)+2015}{\left(2016^{90}+1\right)+2015}< \frac{2016^{100}+1}{2016^{90}+1}=B\)
Vậy \(B>C\)
Giải:
a)Ta có:
C=1957/2007=1957+50-50/2007
=2007-50/2007
=2007/2007-50/2007
=1-50/2007
D=1935/1985=1935+50-50/1985
=1985-50/1985
=1985/1985-50/1985
=1-50/1985
Vì 50/2007<50/1985 nên -50/2007>-50/1985
⇒C>D
b)Ta có:
A=20162016+2/20162016-1
A=20162016-1+3/20162016-1
A=20162016-1/20162016-1+3/20162016-1
A=1+3/20162016-1
Tương tự: B=20162016/20162016-3
B=1+3/20162016-3
Vì 20162016-1>20162016-3 nên 3/20162016-1<3/20162016-3
⇒A<B
Chúc bạn học tốt!
Làm tiếp:
c)Ta có:
M=102018+1/102019+1
10M=10.(102018+1)/202019+1
10M=102019+10/102019+1
10M=102019+1+9/102019+1
10M=102019+1/102019+1 + 9/102019+1
10M=1+9/102019+1
Tương tự:
N=102019+1/102020+1
10N=1+9/102020+1
Vì 9/102019+1>9/102020+1 nên 10M>10N
⇒M>N
Chúc bạn học tốt!
\(A=\frac{2016^{100}+1}{2016^{90}+1}< B=\frac{2016^{99}+1}{2016^{89}+1}\)
k mình nha :))
\(A=\frac{2016^{2016}+2}{2016^{2016}-1}=\frac{2016^{2016}-1+3}{2016^{2016}-1}=\frac{2016^{2016}-1}{2016^{2016}-1}+\frac{3}{2016^{2016}-1}=1+\frac{3}{2016^{2016}-1}\)
\(B=\frac{2016^{2016}}{2016^{2016}-3}=\frac{2016^{2016}-3+3}{2016^{2016}-3}=\frac{2016^{2016}-3}{2016^{2016}-3}+\frac{3}{2016^{2016}-3}=1+\frac{3}{2016^{2016}-3}\)
Vì \(1=1;\frac{3}{2016^{2016}-1}<\frac{3}{2016^{2016}-3}\)nên \(1+\frac{3}{2016^{2016}-1}<1+\frac{3}{2016^{2016}-3}\)
\(=>\)\(A\)\(<\)\(B\)