tinh gia tri bieu thuc :A= [100-1].(100-2 ).[100-3]......[100-n]
cho bieu thuc a=-1/3+1/3^2-1/3^3+1/3^4-1/3^5+...+1/3^100 tinh gia tri cua bieu thuc b=4/a/+1/3^100
tinh gia tri bieu thuc
a/ A= (100 - 1).(100-2)...(100- n) voi n la so tu nhien khac 0,va tich tren co dung 100 thua so
b/B= 13a +19b+4a-2b voi a+b=100
b/B=(13a+4a)+(19b-2b)
B=ax(13+4)+bx(19-2)
B=ax17+bx17
B=17x(a+b)
B=17x100
B=1700
tinh gia tri bieu thuc : a ) : (1+2+3+4+ .............+97+98+99+100) : 5
Tổng các số trong trong ngoặc là:(100+1).[(100-1):1+1]:2=5050
a=5050:5=1010
Cho x+y=2, tinh gia tri cua bieu thuc:
M=3(x^2+y^2)-(x^3+y^3)+1
Bai 2:Cho a+b=5,tinh gia tri bieu thuc:
M=3a^2-2a+3b^2-2b+6ab+100
tinh gia tri bieu thuc A =100+98+96+94+...+2-1-3-5-7-9-...-95-97
tinh gia tri bieu thuc [1+1/100] * [1+1/99]*.....* [1+1/3] * [1+1/2]
Ta có : \(\left(1+\frac{1}{100}\right).\left(1+\frac{1}{99}\right).......\left(1+\frac{1}{3}\right)\left(1+\frac{1}{2}\right)\)
\(=\frac{101}{100}.\frac{100}{99}.\frac{99}{98}......\frac{4}{3}.\frac{3}{2}=\frac{101}{2}\)
\(\left(1+\frac{1}{100}\right).\left(1+\frac{1}{99}\right).....\left(1+\frac{1}{3}\right).\left(1+\frac{1}{2}\right)\)
\(=\frac{101}{100}.\frac{100}{99}.....\frac{4}{3}.\frac{3}{2}=\frac{101}{2}\)
Đặt \(A=\left[1+\frac{1}{100}\right]\cdot\left[1+\frac{1}{99}\right]\cdot....\cdot\left[1+\frac{1}{3}\right]\cdot\left[1+\frac{1}{2}\right]\)
\(A=\frac{101}{100}\cdot\frac{100}{99}\cdot....\cdot\frac{4}{3}\cdot\frac{3}{2}\)
\(A=\frac{101}{\frac{4}{2}}=\frac{101}{2}\)
TINH GIA TRI CUA BIEU THUC
a: A=100-99+98-97....+4 -3 +2=.......
b:B =1+1+1+.......+1 -999(CO 1000 SO 1)=.......
1. tinh gia tri cua bieu thuc
B = 13a + 19b +4a - 2b voi a + b = 100
B = 13a + 19b + 4a - 2b => B = (13a + 4a) + (19b - 2b) => B = 17a + 17b => B = 17(a + b)
Do: a + b = 100 => B = 17 x 100 => B = 1700
tinh gia tri bieu thuc : A=3+3^2+3^3+3^4....3^100
hay giup minh cau nay kho qua !
=>3A=3^2+3^3+3^4+3^5+.....+3^101
=>3A-A=3^101-3
=>2A=3^101-3
=>A=3^101-3/2
vậy A=3^101-3/2