Tính giá trị biểu thức:
\(\frac{2^{50}.3^{61}+2^{90}.3^{16}}{2^{51}.3^{61}+2^{91}.3^{16}}\)
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làm bừa thui,ai tích mình mình tích lại
Số số hạng là :
Có số cặp là :
50 : 2 = 25 ( cặp )
Mỗi cặp có giá trị là :
99 - 97 = 2
Tổng dãy trên là :
25 x 2 = 50
Đáp số : 50
a) \(\frac{7^3.5^8}{49.25^4}=\frac{7^3.5^8}{7^2.5^8}=7\)
b) \(\frac{3^9.25.5^3}{15.625.3^8}=\frac{3^9.5^2.5^3}{3.5.5^4.3^8}=\frac{3^9.5^5}{3^9.5^5}=1\)
c) \(\frac{2^{50}.3^{61}+2^{90}.3^{16}}{2^{51}.3^{61}+2^{91}.3^{16}}=\frac{2^{50}.3^{16}\left(3^{45}+2^{40}\right)}{2^{51}.3^{16}\left(3^{45}+2^{40}\right)}=\frac{1}{2}\)
d) \(\left(\frac{2}{5}-\frac{1}{2}\right)^2+\left(\frac{1}{2}+\frac{3}{5}\right)^2\)
\(=\left(\frac{-1}{10}\right)^2+\left(\frac{11}{10}\right)^2\)
\(=\frac{1}{100}+\frac{121}{100}=\frac{122}{100}=\frac{61}{50}\)
\(=\frac{\left(2^{31}.3^{16}\right).2^{19}.3^{45}+\left(2^{31}.3^{16}\right).2^{59}}{\left(2^{31}.3^{16}\right).2^{20}.3^{45}+\left(2^{31}.3^{16}\right)}\\ =\frac{\left(2^{31}.3^{16}\right).\left(2^{19}.3^{45}+2^{59}\right)}{\left(2^{31}.3^{16}\right).\left(2^{20}.3^{45}+1\right)}\\ =\frac{2^{19}.3^{45}+2^{59}}{2^{20}.3^{45}+1}\)
\(2^{19}.\frac{3^{45}+2^{40}}{2^{20}.3^{45}+1}\)
\(\frac{2^{50}.3^{61}+2^{90}.3^{16}}{2^{51}.3^{61}+2^{31}.3^{16}}=\frac{2^{50}.3^{16}+3^{45}+2^{50}+2^{40}.3^{16}}{2^{31}+3^{20}+2^{31}.3^{16}}\)
\(=556758,4881\)
=\(\frac{2^{50}.+2^{90}}{2^{51}+2^{31}}=\frac{2^{19}}{2^{39}}=\frac{1}{1048576}\)
K nha
a) \(\frac{7^3.5^8}{49.25^4}=\frac{7^3.5^8}{7^2.\left(5^2\right)^4}=7.\frac{5^8}{5^8}=7\)
b) \(\frac{3^9.25.5^3}{15.625.3^8}=\frac{3.3^8.5^2.5^3}{3.5.5^4.3^8}=\frac{5^5}{5^5}=1\)
c) Đề hơi sai roi bạn oi
d) \(\left(\frac{2}{5}-\frac{1}{2}\right)^2+\left(\frac{1}{2}+\frac{3}{5}\right)^2=\left(\frac{-1}{10}\right)^2+\left(\frac{11}{10}\right)^2=\frac{1}{100}+\frac{121}{100}=\frac{61}{50}\)
\(\frac{2^{50}.3^{61}+2^{90}.3^{16}}{2^{51}.3^{61}+2^{31}.3^{61}}\)
\(=\frac{3^{61}\left(2^{50}+2^{90}\right)}{3^{61}\left(2^{51}+2^{31}\right)}\)
\(=\frac{2^{50}+2^{90}}{2^{51}+2^{31}}\)
\(=\frac{2^{31}\left(2^{19}+2^{59}\right)}{2^{31}\left(1+2^{20}\right)}\)
\(=\frac{2^{19}+2^{59}}{1+2^{20}}\)
so sánh
ta có
333444=3334.111=(3334)111
444333=4443.111=(4443)111
So sánh 3334và 4443 ta có
3334=(3.111)4=34 . 1114=81.1114
4443=(4.111)3=43. 1113=64. 1113
Vì 81.1114>64.1113
Suy ra 333444>444333
\(B=\frac{3}{\left(1.2\right)^2}+\frac{5}{\left(2.3\right)^2}+\frac{7}{\left(3.4\right)^2}+....+\frac{61}{\left(30.31\right)^2}\)
\(=\frac{3}{1^2.2^2}+\frac{5}{2^2.3^2}+\frac{7}{3^2.4^2}+...+\frac{61}{30^2.31^2}\)
\(=\frac{2^2-1^2}{1^2.2^2}+\frac{3^2-2^2}{2^2.3^2}+\frac{4^2-3^2}{3^2.4^2}+...+\frac{31^2-30^2}{30^2.31^2}\)
\(=\frac{1}{1^2}-\frac{1}{2^2}+\frac{1}{2^2}-\frac{1}{3^2}+....+\frac{1}{30^2}-\frac{1}{30^2}\)
\(=1-\frac{1}{31^2}=1-\frac{1}{961}=\frac{960}{961}\)
P/s: Bài này chỉ tính được giá trị "gần đúng" của biểu thức thôi nhé!
\(\frac{21}{54}+\frac{3}{75}:\frac{\left(\frac{39}{65}+0,415-\frac{33}{600}\right)\frac{21}{91}}{7^2-18,25+13\frac{15}{36}-16\frac{17}{102}}\)
\(\Leftrightarrow\frac{21}{54}+\frac{3}{75}:\frac{\left(0,6+0,415-0,055\right)0,23}{49-18,25+\frac{483}{36}-\frac{1649}{102}}\)
\(\Leftrightarrow\frac{21}{54}+\frac{3}{75}:\frac{\left(0,6+0,415-0,055\right)0,23}{49-18,25+13,41-16,1}\)
\(\Leftrightarrow\frac{21}{54}+\frac{3}{75}:\frac{0,96.0,23}{28,06}\Leftrightarrow\frac{21}{54}+\frac{3}{75}:\frac{0,2208}{28,06}\)
\(\Leftrightarrow\frac{21}{54}+\left(\frac{3}{75}:\frac{0,2208}{28,06}\right)\Leftrightarrow\frac{21}{54}+\left(\frac{3}{75}.\frac{28,06}{0,2208}\right)=\frac{21}{54}+\frac{61}{12}=\frac{197}{36}\)
P/s: Giải bài này mà mệt cả đầu =((
\(\frac{2^{50}.3^{61}+2^{90}.3^{16}}{2^{51}.3^{61}+2^{91}.3^{16}}\)
\(\Leftrightarrow\frac{2^{50}+2^{90}}{2^{50}.2+2^{90}.2}\)
\(\Leftrightarrow\frac{1+1}{2+2}\)
\(\Leftrightarrow\frac{1}{2}\)
P/s: Không chắc nhé! '-'
Có gì đó sai sai