(1-1\/2^2)(1-1\/3^2) (1-1\/4^2)…(1-1\/10^2)要详细过程,好让我明白...
=(11\/2)(1\/10)=11\/20
(1-1\/2^2)(1-1\/3^2)(1-1\/4^2)…(1-1\/20^2)=?谢
平方差 =(1-1\/2)(1+1\/2)(1-1\/3)(1+1\/3)……(1-1\/20)(1+1\/20)=(1\/2)(3\/2)(2\/3)(4\/3)……(19\/20)(21\/20)中间约分 =(1\/2)(21\/20)=21\/40
计算:(1-1\/2^2)(1-1\/3^2)(1-1\/4^2)…(1-1\/2012)要详细过程
(1-1\/2^2)(1-1\/3^2)(1-1\/4^2)……*(1-1\/20^2)=(1-1\/2)(1+1\/2)(1-1\/3)(1+1\/3)……*(1-1\/20)(1+1\/20)=1\/2*3\/2*2\/3*4\/3……*19\/20*21\/20 =1\/2*(3\/2*2\/3*4\/3……*19\/20)*21\/20 =1\/2*1*21\/20 =21\/40 ...
求一道题的极限:(1-1\/2^2).(1-1\/3^2).(1-1\/4^2).…….(1-1\/n^2)求...
(1-1\/2??)(1-1\/3??)...(1-1\/n??)=(1+1\/2)(1-1\/2)(1+1\/3)(1-1\/3)...(1+1\/n)(1-1\/n)=[(1+1\/2)(1+1\/3)...(1+1\/n)] * [(1-1\/2)(1-1\/3)...(1-1\/n)]=[(3\/2)(4\/3)...(n+1)\/n]...
(1-1\/2^2)(1-1\/3^2)...(1-1\/10^2)的解
每一项因数都可以看做平方差,例如1-1\/2^2利用平方差公式就等于(1-1\/2)(1+1\/2)因此此题就可以这么解答 注(平方差公式为a^2-b^2=(a+b)(a-b) )1-1\/2^2)(1-1\/3^2)...(1-1\/10^2)=(1-1\/2)(1+1\/2)(1-1\/3)(1+1\/3)...(1-1\/10)(1+1\/10)=(1-1\/2)(1...
(1-1\/2^2)(1-1\/3^3)……(1-1\/10^2)
原理是平方差公式:a^2-b^2=(a+b)(a-b)则 1-1\/2^2=1^2-(1\/2)^2=(1+1\/2)(1-1\/2),其他以此类推 所以 (1-1\/2*2)*(1-1\/3*3)*(1-1\/4*4)*···*(1-1\/10*10)=(1+1\/2)*(1-1\/2)*(1+1\/3)(1-1\/3)*(1+1\/4)(1-1\/4)*...*(1+1\/10)*...
帮忙解个数学题:(1-1\/2^2)(1-1\/3^2)(1-1\/4^2)*...*(1-1\/10^2)
原式=(1+1\/2)(1-1\/2)(1+1\/3)(1-1\/3)*。。。(1+1\/10)(1-1\/10)=3\/2*1\/2*4\/3*2\/3*5\/4*3\/4*11\/10*9\/10.其余的都会相互约分掉,最后只会剩下(1-1\/2)和(1+1\/10)1\/2 * 11\/10=11\/20
计算:(1-1\/2^2)(1-1\/3^2)…(1-1\/9^2)(1-1\/10^2)
运用平方差公式:原式=(1- 1\/2)(1+ 1\/2)(1- 1\/3)(1+ 1\/3)*...*(1- 1\/10)(1 + 1\/10)=(1\/2)*(3\/2)*(4\/3)*(3\/4)*(5\/4)*...*(9\/10)*(11\/10)=(1\/2)*(11\/10)=11\/20
(1-1\/2^2)(1-1\/3^2)(1-1\/4^2)...(1-1\/9^2)(1-1\/10^2)
(1-1\/2^2)(1-1\/3^2)(1-1\/4^2)...(1-1\/9^2)(1-1\/10^2)=(1+1\/2)(1-1\/2)(1+1\/3)(1-1\/3)(1+1\/4)(1-1\/4)---(1+1\/9)(1-1\/9)(1+1\/10)(1-1\/10)=3\/2*1\/2*4\/3*2\/3*5\/4*3\/4*---*10\/9**8\/9*11\/10*9\/10 =1\/2*11\/10 =11\/20 ...
计算:(1-1\/2^2)(1-1\/3^2)(1-1\/4^2)...(1-1\/2009^2)(1-1\/2010^2).
1-1\/2009^2)(1-1\/2010^2).=(1-1\/2)(1+1\/2)(1-1\/3)(1+1\/3)(1-1\/4)(1+1\/4)……(1-1\/2009)(1+1\/2009)(1-1\/2010)(1+1\/2010)=(1\/2)(3\/2)(2\/3)(4\/3)(3\/4)(5\/4)……(2008\/2009)(2010\/2009)(2009\/2010)(2011\/2010)=(1\/2)(2011\/2010)=2011\/4020 ...