answer:Let's break down the example `sum = lambda x, y: x + y`. **Lambda Expression Syntax** A lambda expression in Python has the following syntax: ```python lambda arguments: expression ``` In this example: * `lambda` is the keyword that indicates the start of a lambda expression. * `x, y` are the arguments that the lambda expression takes. They are comma-separated and are used in the expression that follows. * `x + y` is the expression that is executed when the lambda expression is called. **Functionality** When you define `sum = lambda x, y: x + y`, you are creating an anonymous function that takes two arguments, `x` and `y`, and returns their sum. Here's how it works: 1. The lambda expression is defined and assigned to the variable `sum`. 2. When you call `sum(2, 3)`, the lambda expression is executed with `x=2` and `y=3`. 3. The expression `x + y` is evaluated, resulting in the value `5`. 4. The value `5` is returned as the result of the lambda expression. **Purpose** Lambda expressions are useful when you need a small, one-time-use function. They are often used: 1. As event handlers or callbacks. 2. As arguments to higher-order functions (functions that take functions as arguments). 3. As a concise way to define simple functions. **Example Usage** Here's an example of using the `sum` lambda expression: ```python sum = lambda x, y: x + y print(sum(2, 3)) # Output: 5 print(sum(4, 5)) # Output: 9 ``` Note that lambda expressions can take any number of arguments, not just two. You can also use them with default arguments, keyword arguments, and even variable numbers of arguments (using the `*args` and `**kwargs` syntax). **Equivalent Function Definition** To illustrate the equivalence between lambda expressions and regular function definitions, here's the same functionality defined using a traditional `def` statement: ```python def sum(x, y): return x + y ``` Both definitions produce the same behavior, but the lambda expression is more concise and often preferred for simple functions.

answer:Let's first understand how the logical AND (`&`) and OR (`|`) operators work in Python: **Logical AND (`&`) Operator:** The logical AND operator is used to combine two or more conditions. It returns `True` if all conditions are true. If any condition is false, it returns `False`. Example: ```python x = 5 y = 3 if x > 0 and y > 0: print(Both numbers are positive.) ``` In this example, the condition `x > 0 and y > 0` is true because both `x` and `y` are positive. **Logical OR (`|`) Operator:** The logical OR operator is used to combine two or more conditions. It returns `True` if at least one condition is true. If all conditions are false, it returns `False`. Example: ```python x = 5 y = -3 if x > 0 or y > 0: print(At least one number is positive.) ``` In this example, the condition `x > 0 or y > 0` is true because `x` is positive. **Enhanced Code Example:** Now, let's enhance the existing code example to use the logical AND (`&`) and OR (`|`) operators: ```python # Python program to get input from user num1 = float(input(Enter first number: )) num2 = float(input(Enter second number: )) if num1 > 0 and num2 > 0: print(Both numbers are positive.) elif num1 < 0 and num2 < 0: print(Both numbers are negative.) elif num1 == 0 or num2 == 0: print(At least one number is zero.) elif num1 > 0 or num2 > 0: print(At least one number is positive.) else: print(Both numbers are negative.) ``` In this enhanced code example, we added two more input variables `num1` and `num2`. We then used the logical AND (`&`) and OR (`|`) operators to combine conditions in the `if` statements. Here's how the code works: 1. The first `if` statement checks if both `num1` and `num2` are positive using the logical AND (`&`) operator. If both numbers are positive, it prints Both numbers are positive. 2. The second `elif` statement checks if both `num1` and `num2` are negative using the logical AND (`&`) operator. If both numbers are negative, it prints Both numbers are negative. 3. The third `elif` statement checks if at least one of `num1` or `num2` is zero using the logical OR (`|`) operator. If at least one number is zero, it prints At least one number is zero. 4. The fourth `elif` statement checks if at least one of `num1` or `num2` is positive using the logical OR (`|`) operator. If at least one number is positive, it prints At least one number is positive. 5. The final `else` statement prints Both numbers are negative if none of the above conditions are true. Note that the order of the `if` and `elif` statements matters. The code will stop executing as soon as it finds a true condition, so the order should be from most specific to least specific.

answer:From the angle addition formula: [ tan x + tan y = frac{sin x cos y + cos x sin y}{cos x cos y} = frac{sin (x + y)}{cos x cos y} = frac{2 sin (x + y)}{cos (x + y) + cos (x - y)}. ] Squaring the given conditions and adding them: [ (sin x + sin y)^2 + (cos x + cos y)^2 = left(frac{5}{13}right)^2 + left(frac{12}{13}right)^2 = frac{25}{169} + frac{144}{169} = 1. ] This implies: [ sin x sin y + cos x cos y = frac{1 - 2}{2} = -frac{1}{2}. ] Thus: [ cos (x - y) = cos x cos y + sin x sin y = -frac{1}{2}. ] Using sum-to-product identities: [ 2 sin left( frac{x + y}{2} right) cos left( frac{x - y}{2} right) = frac{5}{13}, 2 cos left( frac{x + y}{2} right) cos left( frac{x - y}{2} right) = frac{12}{13}. ] Dividing these equations: [ tan left( frac{x + y}{2} right) = frac{5}{12}. ] By the double-angle formula for tangent: [ tan (x + y) = frac{2 cdot frac{5}{12}}{1 - left(frac{5}{12}right)^2} = frac{120}{119}. ] Thus: [ tan^2 (x + y) = left(frac{120}{119}right)^2 = frac{14400}{14161}, ] [ sin^2 (x + y) = frac{14400}{14161 + 14400} = frac{14400}{28561}, ] [ sin (x + y) = frac{120}{169}, quad cos (x + y) = frac{119}{169}. ] Finally: [ frac{2 sin (x + y)}{cos (x + y) + cos (x - y)} = frac{2 cdot frac{120}{169}}{frac{119}{169} - frac{1}{2}} = boxed{frac{240}{119}}. ]

answer:Many people believe that social media is harmful to their mental health. However, others argue that it can be beneficial in certain ways.