实验22用两分法求方程的根 如下的程序是用两分法计算方程在区间[ab]中的根 1)mosa,=|i←0 while b-al 210 a+b c← ←a A:←-b-a a←ciff(a)f(c)>0 b←ciff(c)f(b)>0 1←1+1 f(x):=2x+3.5·x+1.9x-2.5 0 0.75 0.625 0.125 roots(0, 1, f=4 0.5625 0.53125 0.0625 50.53125 0.5625 546 0.03125 6054687505625055468750015625 70.5546875 056250.558593800078125 80.554687505859380.556 0.0039063 90.55664060.55859380.557617200019531 root(f(x),x)=0.558333085242691 f(0.558333085242691)=1.314×10实验22 用两分法求方程的根 如下的程序是用两分法计算方程在区间[a,b]中的根： (1) roots(a,b,f) i ¬ 0 c a + b 2 ¬ Ai, 0 ¬ a A i, 1 ¬ b A i, 2 ¬ c A i, 3 ¬ b - a a ¬ c if f(a)×f(c) > 0 b ¬ c if f(c)×f(b) > 0 i ¬ i + 1 b - a 10- 3 while ³ A := f(x) 2x 3 3.5 x 2 := + × + 1.9×x - 2.5 roots(0, 1,f) 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 0.5 1 0.5 1 0.75 0.5 0.5 0.75 0.625 0.25 0.5 0.625 0.5625 0.125 0.5 0.5625 0.53125 0.0625 0.53125 0.5625 0.546875 0.03125 0.546875 0.5625 0.5546875 0.015625 0.5546875 0.5625 0.5585938 0.0078125 0.5546875 0.5585938 0.5566406 0.0039063 0.5566406 0.5585938 0.5576172 0.0019531 = 2 0 2 5 5 f(x) x x := 0.8 root(f(x), x) = 0.558333085242691 f(0.558333085242691) 1.314 10- 5 = ´