Tinh:4*5+16=....
Tinh C= (5-1).(5+1).(5^2+1).(5^4+1).....(5^16+1)
Lời giải:
$C=(5^2-1)(5^2+1)(5^4+1)(5^8+1)(5^{16}+1)$
$=(5^4-1)(5^4+1)(5^8+1)(5^{16}+1)$
$=(5^8-1)(5^8+1)(5^{16}+1)=(5^{16}-1)(5^{16}+1)$
$=5^{32}-1$
tinh
\(\frac{\left(\frac{2}{5}\right)^9.10^9-\left(\frac{-9}{4}\right)^5:\left(\frac{-3}{16}\right)^{10}}{4^{12}+16^9}\)
Ta có : \(\frac{\left(\frac{2}{5}\right)^9.10^9-\left(\frac{-9}{4}\right)^5:\left(\frac{-3}{16}\right)^{10}}{4^{12}+16^9}\)
=\(\frac{\left(\frac{2}{5}.10\right)^9-\left[\left(\frac{-3}{2}\right)^2\right]^5:\left(\frac{-3}{16}\right)^{10}}{\left(2^2\right)^{12}+\left(2^4\right)^9}\)=\(\frac{4^9-\left(\frac{-3}{2}\right)^{10}:\left(\frac{-3}{16}\right)^{10}}{2^{24}+2^{36}}\)=\(\frac{4^9-\left[\left(\frac{-3}{2}\right):\left(\frac{-3}{16}\right)\right]^{10}}{2^{24}\left(1+2^{12}\right)}\)
=\(\frac{\left(2^2\right)^9-8^{10}}{2^{24}\left(1+2^{12}\right)}\)=\(\frac{\left(2^2\right)^9-\left(2^3\right)^{10}}{2^{24}\left(1+2^{12}\right)}\)=\(\frac{2^{18}-2^{30}}{2^{24}\left(1+2^{12}\right)}\)=\(\frac{2^{18}\left(1-2^{12}\right)}{2^{24}\left(1+2^{12}\right)}\)=\(\frac{1-2^{12}}{2^6\left(1+2^{12}\right)}\)
Không biết đúng hong nha!
Tinh\(\frac{\frac{5}{12}+\frac{3}{4}-1}{3-\frac{5}{6}+\frac{2}{3}}+\frac{\frac{16}{5}+\frac{16}{6}-\frac{16}{7}}{\frac{17}{5}+\frac{17}{6}-\frac{17}{7}}\)
Cac ban giup mik voi, mik k cho! ( 10 k cho 3 nguoi dau tien tra loi cau hoi cua mik)
\(=\frac{\frac{5}{12}+\frac{9}{12}-\frac{12}{12}}{\frac{36}{12}-\frac{10}{12}+\frac{8}{12}}+\frac{16\left(\frac{1}{5}+\frac{1}{6}-\frac{1}{7}\right).}{17\left(\frac{1}{5}+\frac{1}{6}-\frac{1}{7}\right).}\)
\(=\frac{1}{\frac{6}{\frac{17}{6}}}+\frac{16}{17}\)\(=\frac{1}{17}+\frac{16}{17}=1\)
1+5/4+5/8+5/16+5/32+5/64
tinh nhanh
\(1+\frac{5}{4}+\frac{5}{8}+\frac{5}{16}+\frac{5}{32}+\frac{5}{64}\)
\(=\frac{64}{64}+\frac{80}{64}+\frac{40}{64}+\frac{20}{64}+\frac{10}{64}+\frac{5}{64}\)
\(=\frac{64+80+40+20+10+5}{64}\)
\(=\frac{219}{64}\)
\(=\frac{27}{8}\)
1+5/4+5/8+5/16+5/32+5/64
=1+5/4+5/8+5/16+5/32+5/64
=1+(5/4+5/8+5/16+5/32+5/64)
=1+[5x(1/4+1/8+1/16+1/32+1/64)]
A=1/4+1/8+1/16+1/32+1/64
2A=1/2+1/4+1/8+1/16+1/32
2A-A=(1/2+1/4+1/8+1/16+1/32)+(1/4+1/8+1/16+1/32+1/64)
A=1/2-1/64
A=31/64
1+[5x31/64]
=1+155/64
=219/64
tinh nhanh : 5/16: 0,125+1,456: 7/26+4 1/2*0,8
a) 5/6 x 11/4 - 5/4 x 23/6
b) 9/16 x 13/4 - 9/4 x 5/16 + 9/16 x 17/
hay tinh tong:
1/1 x 2 + 1/2 x 3 + 1/3 x 4 + .... + 1/n (n + 1)
chung minh:
1/22 + 1/32 + 1/42 + ..... + 1/n2 < 1
giai dum nhe
Thuc hien phep tinh sau bang cach hop li nhat:
a)5/11+1/2+2/5+6/11+3/4+16/25+5/16
b)19/4+37/100+1/8+132/25+5/2+37/12
5/11+1/2+2/5+6/11+3/4+16/25+5/16
=1441/400
19/4+37/100+1/8+132/25+5/2+37/12
=1933/120
Ban lam sao duooc nhu the giai ra cho minh voi
giup minh
tinh bang cach thuan tien
7/9 x 5/16 : 5/9 x 4/7
7/9 x 5/16 : 5/9 x4/7
=7/9 x 5/16 x9/5 x 4/7
=7/9 x 45/80 x 4/7
=7/9 x 9/16 x 4/7
=7 x 9 x 4 /9 x 16 x 7
=1/4
4+5+6+7+8+9+10+11+12+13+14+15+16
tinh nhanh
4+5+6+7+8+9+10+11+12+13+14+15+16
= (4+16)+(5+15)+(7+13)+(8+12)+(9+11)+10
=20+20+20+20+20+10
=110
tick nha