Rut gon bieu thuc: A=1+ 1/2+ 1/22+ 1/23+ ... +1/22012
GIUP MINH NHANH NHE
Giup minh nhe!!
1. Rut gon bieu thuc:
a) \(A=\sqrt{x-2+2\sqrt{x-3}}+\sqrt{x+6+6\sqrt{x-3}}voix>=3\)
\(A=\sqrt{x-2+2\sqrt{x-3}}+\sqrt{x+6+6\sqrt{x-3}}\\ A=\sqrt{x-3+2\sqrt{x-3}+1}+\sqrt{x-3+2.3.\sqrt{x-3}+9}\\ A=\sqrt{\left(\sqrt{x-3}+1\right)^2}+\sqrt{\left(\sqrt{x-3}+3\right)^2}\\ A=\left|\sqrt{x-3}+1\right|+\left|\sqrt{x-3}+3\right|\\ A=\sqrt{x-3}+1+\sqrt{x-3}+3\\ A=2\sqrt{x-3}+4\)
cho bieu thuc a^3+2a^2-1/a^3+2a^2+2a+1
a) Rut gon bieu thuc
b)Chung minh rang neu a la so nguyen thi gia tri tim duoc cua bieu thuc o cau a) la 1 phan so toi gian
Rut gon bieu thuc
A= 1+1/2+1/2^+1/2^+....+1/2^2017
\(A=1+\dfrac{1}{2}+\dfrac{1}{2^2}+...+\dfrac{1}{2^{2017}}\)
\(\Rightarrow2A=2+1+\dfrac{1}{2}+\dfrac{1}{2^2}+...+\dfrac{1}{2^{2016}}\)
\(\Rightarrow2A-A=\left(2+1+\dfrac{1}{2}+\dfrac{1}{2^3}+...+\dfrac{1}{2^{2016}}\right)\)
\(-\left(1+\dfrac{1}{2}+\dfrac{1}{2^2}+...+\dfrac{1}{2^{2017}}\right)\)
\(\Rightarrow A=2-\dfrac{1}{2^{2017}}=\dfrac{2^{2018}-1}{2^{2017}}\)
\(A=1+\dfrac{1}{2}+\dfrac{1}{2^2}+...+\dfrac{1}{2^{2017}}\)
\(2A=\left(2+1+\dfrac{1}{2}+...+\dfrac{1}{2^{2016}}\right)\)
\(2A-A=\left(2+1+\dfrac{1}{2}+...+\dfrac{1}{2^{2016}}\right)-\left(1+\dfrac{1}{2}+\dfrac{1}{2^2}+...+\dfrac{1}{2^{2017}}\right)\)
\(A=2-2^{2017}\)
Giup minh nhe!!
1. Rut gon bieu thuc:
a) \(A=\sqrt{11-6\sqrt{2}}+3+\sqrt{2}\)
b) \(B=\sqrt{12+2\sqrt{11}}+\sqrt{12-2\sqrt{11}}\)
2. Rut gon bieu thuc:
a) \(A=\sqrt{x-2+2\sqrt{x-3}}+\sqrt{x+6+6\sqrt{x-3}},voix>=3\)
3. Tim GTNN cua bieu thuc:
a) \(A=\sqrt{4x^2-12x+9}+\sqrt{x^2-10x+25}+\sqrt{9x^2-6x+1}+\sqrt{16x^2-72x+81}\)
b) \(B=\dfrac{1}{2}\sqrt{x^2}+\sqrt{x^2-2x+1}\)
1)
a)
\(\sqrt{11-6\sqrt{2}}=\sqrt{2-2.3.\sqrt{2}+9}=\left|\sqrt{2}-3\right|=3-\sqrt{2}\)
\(A=3-\sqrt{2}+3+\sqrt{2}=6\)
b)
\(B^2=24+2\sqrt{12^2-4.11}=24+2\sqrt{100}=24+20=44\)
\(B=\sqrt{44}=2\sqrt{11}\)
cho A= (2x-1)^2 -5x.(x-1)+2.(x+1).(x-2) rut gon bieu thuc A
\(A=\left(2x-1\right)^2-5x\left(x-1\right)+2\left(x+1\right)\left(x-2\right)\)
\(=4x^2-4x+1-5x^2+5x+2\left(x^2-x-2\right)\)
\(=x^2-x-3\)
rut gon bieu thuc:(1/2+1)(1/3+1)(1/4+1).....(1/99+1)
Bài này có rắc rối đâu em?
Thực hiện phép tính trong ngoặc lại là ra dạng (n+1)/n.
1 dãy các số liên tục kéo dài nhân với nhau thì triệt tiêu là xong!
Chúc em học tốt!
rut gon bieu thuc
(2x-1).(x-2)
rut gon bieu thuc
B=((3/√(1+a))+√(1-a)):((3/√(1+a^2))+1)
rut gon bieu thuc (6x-1)^2+(6x+1)^2-2(1+6x)(6x+1)