分类：教育/科学-理工学科-数学
问题：问一道英文数学证明题√N+1
√N+1-√N=1/√N+1-√N 这个证明很简单use this to elain why √101 is close to,but slightly less than,10.05find the roots of x^2+7x-13=0,giving your answers correct to 2 decimal places.
回答：√101-√100 = 1/(√101+√100）＜ 1/(√100+√100) = 1/20
--->√101 ＜ 10+1/20 = 10.05

x²+7x-13=0
--->x = (-7±√101)/2 = (-7±10.05)/2 ≈ -8.525 or 1.525