\(\left(-1\right)^{2n}.\left(-1\right)^n.\left(-1\right)^n+1=\left(-1\right)^{2n+n+n}+1=\left(-1\right)^{4n}+1=1+1=2\)
\(\left(-1\right)^{2n}.\left(-1\right)^n.\left(-1\right)^n+1=\left(-1\right)^{2n+n+n}+1=\left(-1\right)^{4n}+1=1+1=2\)
Cho bieu thuc A = \(^{x2+4x+3}\)
a Tinh gia tri bieu thuc tai x= \(\frac{-1}{2}\)
b Tinh gia tri x de bieu thuc A bang 0
bai 2 ; TINH GIA TRI BIEU THUC A = XN + \(\frac{1}{X^N}\)
GIA SU X2 + X+ 1 = 0
Tinh gia tri cua bieu thuc
M=5xy-10=3y tai x=2 ; y=-3
N =2(x^2-1) +3x-2 tai x=-1
tinh gia tri bieu thuc: A=(1-1/(1+2))(1-1/(1+2+3))...(1-1/(1+2+3+...+2006))
cho bieu thuc:
A=(6-2/3+1/2)-(5+5/3-3/2)-(3-7/3+5/2)
hay tinh gia tri cua A theo hai cach
cach 1:truoc het tinh gia tri tung bieu thuc trong ngoac
cach 2:bo dau ngoac roi nhom cac so hang thich hop
tinh gia tri bieu thuc A=2^2015-(2^2014+2^2013+...+2+1)
tinh gia tri bieu thuc
/a+b-c/
biet A= -5 ; B=2;C=1
BIET / LA GIA TRI tuyet doi
tinh gia tri lon nhat cua bieu thuc
P=x.y
biet x+y =1
cho a b c khac 0 va a-b-c=0 tinh gia tri bieu thuc A=(1-c/a) (1-a/b) (1+b/c)