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1 4 ⋅ 10 + 1 10 ⋅ 16 + 1 16 ⋅ 22 + 1 22 ⋅ 28 + 1 28 ⋅ 34 . 4 \ \压裂{1}{cdot10} + \压裂{1}{10 \ cdot16} + \压裂{1}{16 \ cdot22} + \压裂{1}{22 \ cdot28} + \压裂{1}{28 \ cdot34}。 4⋅101+10⋅161+16⋅221+22⋅281+28⋅3.41.
3. 1 ⋅ 2 ⋅ 3. + 5 2 ⋅ 3. ⋅ 4 + 7 3. ⋅ 4 ⋅ 5 + ⋯ + 81 40 ⋅ 41 ⋅ 42 = ? \frac{3}{1 \cdot 2 \cdot 3} + \frac{5}{2 \cdot 3 \cdot 4} + \frac{7}{3 \cdot 4 \cdot 5} + \cdots + \frac{81}{40 \cdot 41 \cdot 42} = ? 1⋅2⋅3.3.+2⋅3.⋅45+3.⋅4⋅57+⋯+40⋅41⋅4281=?
1 4 + 7 + 1 7 + 10 + ⋯ + 1 397 + 400 . \压裂{1}{\ sqrt {4} + \ sqrt{7}} + \压裂{1}{\ sqrt {7} + \ sqrt {10}} + \ cdots + \压裂{1}{\ sqrt {397} + \ sqrt{400}}。 4 +7 1+7 +10 1+⋯+3.97 +400 1.
假设 一个 , b , c , a, b, c, 一个,b,c,而且 d d d常数是否对所有实数都成立 x x x使所有分母都非零的: 10 x ( x + 10 ) + 10 ( x + 5 ) ( x + 15 ) + 10 ( x + 10 ) ( x + 20. ) + 10 ( x + 15 ) ( x + 25 ) + 10 ( x + 20. ) ( x + 30. ) = 一个 ( x 2 + 30. x + 75 ) x ( x + b ) ( x + c ) ( x + d ) . {对齐}& \ \开始压裂{10}{x (x + 10)} + \压裂{10}{(x + 5) (x + 15)} + \压裂{10}{(x + 10) (x + 20 )} \\ &+ \ 压裂{10}{(x + 15) (x + 25)} + \压裂{10}{(x + 20) (x + 30 )} \\ &= \ 压裂{(x ^ 2 + 30 x + 75)} {x (x + b) (x + c) (x + d)}。结束\{对齐} x(x+10)10+(x+5)(x+15)10+(x+10)(x+20)10+(x+15)(x+25)10+(x+20)(x+3.0)10=x(x+b)(x+c)(x+d)一个(x2+3.0x+75).的价值是什么 一个 + b + c + d ? a + b + c + d ? 一个+b+c+d?
如果 f ( x ) = 4 x 2 − 1 , f (x) = 4 x ^ 2 - 1, f(x)=4x2−1,的价值是什么
1 f ( 1 ) + 1 f ( 2 ) + 1 f ( 3. ) + ⋯ + 1 f ( 84 ) ? f(1) \压裂{1}{}+ \压裂{1}{f(2)} + \压裂{1}{f (3)} + \ cdots + \压裂{1}{f (84)} ? f(1)1+f(2)1+f(3.)1+⋯+f(84)1?
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