111

159-6.py

@@ -1,6 +1,6 @@
 import math
 
-
+#把函数改成题干的形式#####################
 def f(x):
     return x**2 - 30
 
@@ -10,12 +10,14 @@ def df(x):
 # 牛顿方法求解方程
 def NewtonSolve(fx, dfx, x0, err, N0):
     count = 0
+    print(f"k={count}, x0={x0}")
     x1 = x0 + 1 + err
     while abs(x1 - x0) > err or abs(fx(x1)) > err: # 添加条件修正根误差太大的问题
         if abs(dfx(x1)) < 1e-10:
             return None, 0
         x1 = x0 - fx(x0) / dfx(x0)
         count += 1
+        print(f"k={count}, x{count}={x1},x1-x0={abs(x1-x0)}")
         if count > N0:
             return None, -1
         x0 = x1
@@ -34,6 +36,6 @@ if __name__ == "__main__":
     err = 1e-4
     N0 = 100
 
-    x0 = FindRootZone(f, 5, 6, 0.01)
+    x0 = FindRootZone(f, 5, 6, 0.1) # 查找f的根的区间与步长，改成题干对应的范围
     result,status = NewtonSolve(f, df, x0, err,N0)
     print(f"sqrt(30) = {result:.3f}")