Ответ: Ось так?

import numpy as np

import matplotlib.pyplot as plt

def vector_calc():

   print("Vector calculator")

   print("Enter the size of the vector")

   size = int(input())

   print("Enter the vector")

   vector = np.array([float(input()) for i in range(size)])

   print("Enter the operation")

   operation = input()

   if operation == "+":

       print("Enter the second vector")

       vector2 = np.array([float(input()) for i in range(size)])

       print(vector + vector2)

   elif operation == "-":

       print("Enter the second vector")

       vector2 = np.array([float(input()) for i in range(size)])

       print(vector - vector2)

   elif operation == "*":

       print("Enter the second vector")

       vector2 = np.array([float(input()) for i in range(size)])

       print(vector * vector2)

   elif operation == "/":

       print("Enter the second vector")

       vector2 = np.array([float(input()) for i in range(size)])

       print(vector / vector2)

   elif operation == "scalar":

       print("Enter the second vector")

       vector2 = np.array([float(input()) for i in range(size)])

       print(np.dot(vector, vector2))

   elif operation == "norm":

       print(np.linalg.norm(vector))

   elif operation == "plot":

       print("Enter the function")

       func = input()

       x = np.linspace(-10, 10, 1000)

       y = eval(func)

       plt.plot(x, y)

       plt.show()

   else:

       print("Invalid operation")

if __name__ == "__main__":

   vector_calc()