answer:Certainly! Here are some additional steps you can take to implement a user authentication system and prevent unauthorized access to certain features on your travel recommendation website: 1. Install the Devise gem: Devise is a widely used Ruby gem for user authentication in Rails. You can install it by adding `gem 'devise'` to your Gemfile and then running `bundle install`. 2. Generate a User model: You can generate a User model by running the following command in your terminal: `rails generate devise User`. This will create a migration file and a User model with default fields such as email and password. 3. Run migrations: You’ll need to run `rails db:migrate` to create the database table for your new User model. 4. Set up authentication constraints: You'll want to set up constraints on which parts of your site can be accessed by authenticated users versus guests. You can do this in your controller actions by calling `before_action :authenticate_user!` to ensure that users are signed in before accessing certain features. 5. Implement login and logout functionality: This requires creating a login and logout action within your User controller. Devise provides useful helper functions such as `user_signed_in?`, `current_user` and `user_session` that you can use to verify if a user is currently logged in or not. 6. Customize the User model and views: Devise allows you to customize the User views so that they correspond to your website's design. You can also add additional fields to the User model, depending on the information you want to collect from users, such as names or travel preferences. 7. Test your authentication system: It’s important to test your authentication system thoroughly to ensure that it's secure and user-friendly. You could use a browser plugin like Wappalyzer, which can detect the presence of Devise and other popular Ruby on Rails technologies. By following these steps, you can create a secure and user-friendly travel recommendation website using Ruby on Rails and the Expedia API which allows users to authenticate themselves and utilize the website without any unauthorized access.

answer:# quadratic equation: ax^2 + bx + c = 0 import math a = float(input("Enter value of a: ")) b = float(input("Enter value of b: ")) c = float(input("Enter value of c: ")) # calculate discriminant discriminant = b**2 - 4*a*c # check if roots are real, imaginary or equal if discriminant > 0: # calculate two real roots root1 = (-b + math.sqrt(discriminant)) / (2*a) root2 = (-b - math.sqrt(discriminant)) / (2*a) print("The roots are real and different.") print("Root 1 = ", root1) print("Root 2 = ", root2) elif discriminant ==0: # calculate equal roots root1 = (-b + math.sqrt(discriminant)) / (2*a) print("The roots are real and equal.") print("Root 1 = Root 2 = ", root1) else: # calculate two imaginary roots real_part = -b/(2*a) imaginary_part = math.sqrt(abs(discriminant))/(2*a) print("The roots are complex and different.") print("Root 1 = ", real_part, "+", imaginary_part, "i") print("Root 2 = ", real_part, "-", imaginary_part, "i")

answer:No, this program can only solve quadratic equations. For solving cubic equations, we need to use a different formula called the cubic formula. However, the cubic formula is more complicated than the quadratic formula, and the process of finding roots may involve complex numbers.

answer:Sure! The cubic formula is used to find the roots of a cubic equation of the form ax^3 + bx^2 + cx + d = 0. Here are the steps to use the cubic formula: 1. Divide both sides of the equation by `a` to get it in the form x^3 + bx^2 + cx + d/a = 0. 2. Define the coefficient `p = b/a`, `q = c/a`, and `r = d/a` 3. Define the discriminant `D = (4p^3-27q^2)` 4. If `D > 0`, then there is only one real root and two complex roots. If `D = 0`, then there is only one real root, and if `D < 0`, then all three roots are complex. 5. If `D >= 0`, define `A` and `B` as follows: A = (q + (D)^1/2)/2^(1/3) + (q - (D)^1/2)/2^(1/3) B = (q + (D)^1/2)/2^(1/3) - (q - (D)^1/2)/2^(1/3) 6. The real root of the cubic equation is given by `x = A - p/3A - B/3` 7. The complex roots can be written as `-1/2(A + B) - p/3 +/- (A - B)i*sqrt(3)/2` Note that this formula can be quite complicated, and sometimes the expressions for A and B can be long and difficult to simplify. So, you may need to factor out some terms where possible to simplify the formula.