填入:29/4(f(10)-f(5))/(10-5)=(13-7)/5=6/5f'(x)=1+1/(2√(x-1))f'(ξ)=1+1/(2√(ξ-1))得 1+1/(2√(ξ-1))=6/5解得 ξ=29/4所以 ξ=29/4
