第1个回答 2013-07-18
1/(3+√3)= (1/√3) * (1/(√3+1))=(1/√3) * (√3 - 1)/2 = (1-1/√3)/2
1/(5√3+3√5) = (1/√15) * (1/(√5+√3)) =(1/√15) *(√5-√3)/2 = (1/√3 - 1/√5)/2
1/(7√5+5√7) = (1/√35) * (1/(√7+√5)) =(1/√35) *(√7-√5)/2 = (1/√5 - 1/√7)/2
…………
1/(49√47+47√49) = (1/√(49*47)) * (1/(√49+√47)) =(1/√(49*47)) *(√49-√47)/2 = (1/√47 - 1/√49)/2
所以,这个算式的结果:
= 1/2 - (1/√49)/2 = 1/2 - 1/14 = 6/14 = 3/7