求解GMAT一道数学题[1/(2n-1)!]-[1/(2n+1)!]简化后等于an^2+bn+c,问a+b+c等于多少?

求解GMAT一道数学题[1/(2n-1)!]-[1/(2n+1)!]简化后等于an^2+bn+c,问a+b+c等于多少? 求解一道数学题,1题 GMAT一道数学题, 一道GMAT的数学题 GMAT一道数学题（data sufficiency）Is the integer n odd?(1)n is divisible by 3(2)2n is divisible by twice as many as positive integers as n 一道关于GMAT的数学题 求解简单数学题2+3+…+(n-1)=? 求解一道数列求和的数学题.求Sn=1∧2-2∧2+3∧2-4∧2+...+（-1)∧(n-1)×n∧2 一道Gmat数学题!For any positive integer n,the sum of the first n positive integers equals n(n+1)/2.what is the sum of all the even integers between 99 and 301? 一道GMAT数学题求解.If y≠3 and 3x/y is a prime integer greater than 2,which of the following must be true?1.x=y2.y=13.x and y are prime integers.A NoneB 1 onlyC 2 onlyD 3 onlyE 1 and 3答案给出的是A，我觉得选B，请问条件1有什 求解一道GMAT数学题……Is the number of members of ClubXgreater than thenumber of members of Club Y (1) Of the members of Club X,20 percent are alsomembers of Club Y.(2) Of the members of Club Y,30 percent are alsomembers of Club X.这是Data 一道GMAT数学题……求解……Ifthe average (arithmetic mean) of six numbers is 75,how many of the numbers are equal to 75 (1) None of the six numbers is less than 75.(2) None of the six numbers is greater than 75. GMAT一道数学题(data sufficiency)求解Is the measure of one of the interior of quadrilateral ABCD eaqual to 60 degrees?(1)Two of the interior angels are right angels.(2)The degree measure of angel ABC is twice the degree measure of angel BCD.为 一道数学题1/2[1-1/(6n+1)] 求解一道数学题；（xy-1)^2+(x+y-2)(x+y-2xy) 分解因式 求解一道数学题；（xy-1)^2+(x+y+2)(x+y+2xy) 分解因式 求解一道含绝对值不等式的数学题|x＋2|＋|x－1|＞3 一道数学题大神求解!