Tính nhanh:
a) \(\left(2017^1\right)^{2.4.6.8...2016}\)
b)\(2017^{\left(225-1^2\right).\left(225-2^2\right).\left(225-3^2\right)....\left(225-56^2\right)}\)
Tính nhanh: 2017\(^{\left(225-1^2\right)\left(225-2^2\right)\left(225-3^2\right)...\left(225-56^2\right)}\)
\(2017\cdot \left(225-1^2\right)\left(225-2^2\right)....\left(225-15^2\right).....\left(225-56^2\right)\)
\(=2017\cdot224\cdot221\cdot\cdot\cdot\cdot\cdot0\cdot\cdot\cdot\left(-2911\right)\)
\(=0\)
Bài 1: Tính nhanh
a) \(\left(2017^1\right)^{2.4.6.8....2016}\)
b) \(2017^{\left(225-1^2\right).\left(225-2^2\right).\left(225-3^2\right)....\left(225-56^2\right)}\)
Bài 2: Tính
A = \(\dfrac{2.5^{22}-9.5^{21}}{25^{10}}\): \(\dfrac{5.\left(3.7^{15}-19.7^{14}\right)}{7^{16}+3.7^{15}}\)
B = \(\dfrac{4^6.9^5+6^9.1^{20}}{-8^4.3^{12}-6^{11}}\)
C = \(\dfrac{6^3+3.6^2+3^3}{-27}\)
D = \(\dfrac{1}{1-\dfrac{1}{1-2^{-1}}}\)+ \(\dfrac{1}{1+\dfrac{1}{1+2^{-1}}}\)
M = \(2^{10}-2^9-2^8-2^7-....-1\)
Giúp mk với. Mk cần gấp
1b. Ta thấy \(225-15^2=0\)
Mọi số nhân với 0 đều = 0
=> \(2017^0=1\)
2.
\(A=\dfrac{2.5^{22}-9.5^{21}}{25^{10}}:\dfrac{5\left(3.7^{15}-19.7^{14}\right)}{7^{16}+3.7^{15}}=\dfrac{5^{21}\left(2.5-9\right)}{5^{20}}:\dfrac{5.7^{14}\left(3.7-19\right)}{7^{15}\left(7+3\right)}=5.1:\dfrac{5.7^{14}.2}{7^{15}.10}=5:\dfrac{1}{7}=35\)
\(C=\dfrac{6^3+3.6^2+3^3}{-27}=\dfrac{2^3.3^3+3.2^2.3^2+3^3}{-3^3}=\dfrac{3^3\left(2^3+2^2+1\right)}{-3^3}=-\left(8+4+1\right)=-13\)
Tinh nhanh :\(A=1994^{\left(225-1^2\right)\left(225-2^2\right)...\left(225-50^2\right)}\)
A=1
vì có mũ là 225-15^2=0
suy ra cả mũ bằng 0
hay A=1994^0=1
Tính :
1 + 3 + 5 + 7 + ... + (2n - 1) = 225
Giải :
Theo công thức tính dãy số , ta có :
\(\frac{\left\{\left[\left(2n-1\right)-1\right]:2+1\right\}.\left[\left(2n-1\right)+1\right]}{2}=225\)
\(\frac{\left\{\left[2n-2\right]:2+1\right\}.2n}{2}=225\)
\(\left\{\left[2n-2\right]:2+1\right\}.n=450\)(Lượt giản thừa số 2)
\(\left\{\frac{2n-2}{2}+1\right\}.n=225\)
\(\left\{\frac{2n-2}{2}+\frac{2}{2}\right\}.n=225\)
\(\frac{2n-2+2}{2}.n=225\)
\(\frac{2n}{2}.n=225\)
\(n^2=225\)
\(\Rightarrow n=\sqrt{225}=15\)
Tinh nhanh : \(A=1994^{\left(225-1^2\right)\left(225-2^2\right)...\left(222-50^2\right)}\)
Tính giá trị của các biểu thức:
a) \(\dfrac{-3}{2}\sqrt{9-4\sqrt{5}}+\sqrt{\left(-4\right)^2\left(1+\sqrt{5}\right)^2}\)
b) \(\left(1+\dfrac{1}{tan^225^0}\right)sin^225^0-tan55^0.tan35^0\)
a) Ta có: \(-\dfrac{3}{2}\sqrt{9-4\sqrt{5}}+\sqrt{\left(-4\right)^2\cdot\left(1+\sqrt{5}\right)^2}\)
\(=\dfrac{-3}{2}\left(\sqrt{5}-2\right)+4\cdot\left(\sqrt{5}+1\right)\)
\(=\dfrac{-3}{2}\sqrt{5}+3+4\sqrt{5}+4\)
\(=\dfrac{5}{2}\sqrt{5}+7\)
b) Ta có: \(\left(1+\dfrac{1}{\tan^225^0}\right)\cdot\sin^225^0-\tan55^0\cdot\tan35^0\)
\(=\dfrac{\tan^225^0+1}{\tan^225^0}\cdot\sin25^0-1\)
\(=\left(\dfrac{\sin^225^0}{\cos^225^0}+1\right)\cdot\dfrac{\cos^225^0}{\sin^225^0}\cdot\sin25^0-1\)
\(=\dfrac{\sin^225^0+\cos^225^0}{\cos^225^0}\cdot\dfrac{\cos^225^0}{\sin25^0}-1\)
\(=\dfrac{1}{\sin25^0}-1\)
\(=\dfrac{1-\sin25^0}{\sin25^0}\)
Bài 5 : Tính nhanh :
a, A =\(1993^{1^{2\times3\times4\times.....\times1994}}\)
b, B = \(1994^{\left(225-1^2\right)\times\left(225-2^2\right)\times....\times\left(225-50^2\right)}\)
c, C =\(\frac{2^{10}\times3^{31}+2^{40}\times3^6}{2^{11}\times3^{31}+2^{41}\times3^6}\)
d, D = \(\left(1+2+2^2+2^3+.....+2^{2003}+2^{2004}\right)-2^{2005}\)
Ta có : D = (1 + 2 + 22 + 23 + ....... + 22004) - 22005
Đặt A = 1 + 2 + 22 + 23 + ....... + 22004
=> 2A = 2 + 22 + 23 + ....... + 22005
=> 2A - A = 22005 - 1
=> A = 22005 - 1
Thay vào ta có : D = (1 + 2 + 22 + 23 + ....... + 22004) - 22005
=> D = 22005 - 1 - 22005
=> D = -1
cậu làm còn thiếu bước kìa Nguyễn Việt Hoàng
giúp mình giải bài này với
Tính: \(2018^{\left(225-1^2\right)\cdot\left(225-2^2\right)\cdot\cdot\cdot\left(225-50^2\right)}\)
MỌI NGƯỜI ƠI GIÚP MÌNH NHÉ TT-TT
Bài 6 ; tính nhanh:
a, A =\(1993^{1^{2\times3\times4\times......\times1994}}\)
b, B =\(1994^{\left(225-1^2\right)\times\left(225-2^2\right).......\left(225-50^2\right)}\)
c, C =\(\frac{2^{10}\times3^{31}+2^{40}\times3^6}{2^{11}\times3^{31}+2^{41}\times3^6}\)
a,\(A=1993^{1^{2\times3\times4\times...\times1994}}=1993^1=1993\)
b,\(B=1994^{\left(225-1^2\right)\times\left(225-2^2\right).....\left(225-50^2\right)}\)
\(=1994^{\left(225-1^2\right)\times\left(225-2^2\right)...\left(225-15^2\right)...\left(225-50^2\right)}\)
\(=1994^{\left(225-1^2\right)\times\left(225-2^2\right)...\left(225-225\right)...\left(225-50^2\right)}\)
\(=1994^{\left(225-1^2\right)\times\left(225-2^2\right)...\times0\times...\left(225-50^2\right)}\)
\(=1994^0=1\)
c, \(C=\frac{2^{10}\times3^{31}+2^{40}\times3^6}{2^{11}\times3^{31}+2^{41}\times3^6}\)
\(=\frac{2^{10}\times3^6\times\left(1\times3^{25}+2^{30}\times1\right)}{2^{11}\times3^6\times\left(1\times3^{25}+2^{30}\times1\right)}\)
\(=\frac{2^{10}}{2^{11}}=\frac{1}{2}\)