Đáp án : 0

Đương nhiên là bằng 0

      A=100/1 x 2 + 100/2 x 3 + 100/3 x 4 +...+100/99 x 100

A/100=1/1 x 2 + 1/2 x 3 + 1/3 x 4 +...+1/99 x 100

A/100=2-1/1x2 + 3-2/2x3 + ... + 100-99/99x100

A/100=1-1/2 + 1/2-1/3+...+1/99-1/100

A/100=1-1/100

A/100=99/100

A=99/100x100=99

Vậy A=99.

Ta có:

\(\frac{100}{1.2}+\frac{100}{2.3}+\frac{100}{3.4}+...+\frac{100}{99.100}\)

\(\Rightarrow100.\left(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{99.100}\right)\)

\(\Rightarrow100.\left(\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{99}-\frac{1}{100}\right)\)

\(\Rightarrow100.\left(\frac{1}{1}-\frac{1}{100}\right)\Leftrightarrow100.\frac{99}{100}=99\)

\(\text{Ta có :}\)

\(\frac{100}{1.2}+\frac{100}{2.3}+\frac{100}{3.4}+...+\frac{100}{99.100}\)

\(=100.\left(\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{99}-\frac{1}{100}\right)\)

\(100.\left(\frac{1}{1}-\frac{1}{100}\right)=100.\frac{99}{100}=99\)

Khi Nhân 99/  100 với một số ta được kết quả bằng 100 .

Vậy phép nhân đó là:.......….…

Giảinhanh giúp mình với

A=x¹⁰-100x⁹+100x⁸-100x⁷+...+100x²-100x+1 tại x=99

=>A=x¹⁰-(x+1)x⁹+(x+1)x⁸-(x+1)x⁷+...+(x+1)x²-(x+1)x+1

A=x¹⁰-x¹⁰-x⁹+x⁹+x⁸-x⁸-x⁷+...+x³+x²-x²-x+1

= 1-x

=1-99

=-98

\(x+\frac{1}{100}+x+\frac{2}{100}+...+x+\frac{99}{100}=100x\)

\(\Rightarrow99x+\frac{1+2+...+99}{100}=100x\)

\(\Rightarrow100x-99x=\frac{\frac{\left(1+99\right).99}{2}}{100}\)

\(\Rightarrow x=\frac{99}{2}\)

Vậy \(x=\frac{99}{2}\)

\(x+\frac{1}{100}+x+\frac{2}{100}+x+\frac{3}{100}+...+x+\frac{99}{100}=100x\)

\(\Leftrightarrow99x+\frac{1+2+3+...+99}{100}=100x\)

\(\Leftrightarrow x=\frac{1+2+3+...+99}{100}\)

\(\Leftrightarrow x=\frac{\frac{99\left(99+1\right)}{2}}{100}\)

\(\Leftrightarrow x=\frac{4950}{100}\)

\(\Leftrightarrow x=\frac{99}{2}\)

\(x+\frac{1}{100}+x+\frac{2}{100}+x+\frac{3}{100}+...+x+\frac{99}{100}=100x\)

\(\frac{100x+1}{100}+\frac{100x+2}{100}+...+\frac{100x+99}{100}=100x\)

\(\frac{9900x+4950}{100}=100x\)

\(9900x+4950=10000x\)

\(x=49,5\)

\(\left(1-\dfrac{99}{99}\right)\times\left(1-\dfrac{100}{100}\right)\times...\times\left(1-\dfrac{2010}{2010}\right)\)
\(=\left(1-1\right)\times\left(1-1\right)\times...\times\left(1-1\right)\)
\(=0\times0\times...\times0\)
\(=0\)

=0

=0

=0

A=x10-100x9+100x8-100x7+...+100x2-100x+1 tại x=99

=>A=x10-(x+1)x9+(x+1)x8-(x+1)x7+...+(x+1)x2-(x+1)x+1

A=x10-x10-x9+x9+x8-x8-x7+...+x3+x2-x2-x+1

= 1-x

=1-99

=-98