#正割法计算方程
def SecantSolve(fx, x0, x1, err=1e-10, N0=100):
    count = 0
    print(f"k={count}: x{count}={x0}, f(x{count})={fx(x0)}")
    count += 1
    print(f"k={count}: x{count}={x1}, f(x{count})={fx(x1)}")
    count += 1
    while abs(x1 - x0) > err or abs(fx(x1)) > err:
        if fx(x1) == fx(x0):
            return None,0
        x2 = x1 - fx(x1) * (x1 - x0) / (fx(x1) - fx(x0))
        print(f"k={count}: x{count}={x2}, f(x{count})={fx(x2)}")
        count += 1
        if count > N0:
            return None,-1
        x0 = x1
        x1 = x2
    return x2,1


if __name__ == "__main__":
    err = 1e-5
    N0 = 100

    x0 = 0.3
    x1 = 0.4
    fx = lambda x: x**4 - 3*x + 1

    result, status = SecantSolve(fx, x0, x1, err, N0)
    if status == 1:
        print(f"fx收敛 解为: {result}")
    elif status == -1:
        print("fx不收敛")
    else:
        print("分母为0，无法收敛")