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question:In the Cartesian coordinate system, two points A(0, a) and B(0, b) are given on the positive y-axis, where a > b > 0. Point C is on the positive x-axis and is such that angle ACB is maximized. What are the coordinates of point C?

answer:To solve this problem, we need to maximize the angle (angle ACB) where (A(0, a)), (B(0, b)), and (C(x, 0)) are points in the Cartesian coordinate system with (a > b > 0).Let's break it down into manageable steps:1. Understand the Geometry: - Points (A) and (B) are on the (y)-axis with coordinates (A(0, a)) and (B(0, b)). - Point (C) is on the (x)-axis with coordinates (C(x, 0)). - We need to maximize (angle ACB).2. Use Trigonometric Formulas: The tangent of angle ( theta ) (where (theta = angle ACB)) can be expressed using the slopes of lines (AC) and (BC): [ tan(angle ACB) = left| frac{text{slope of } AC - text{slope of } BC}{1 + text{slope of } AC cdot text{slope of } BC} right| ] Using the coordinates: - Slope of (AC = frac{a - 0}{0 - x} = -frac{a}{x}) - Slope of (BC = frac{b - 0}{0 - x} = -frac{b}{x}) Substituting these into the tangent formula: [ tan(angle ACB) = left| frac{-frac{a}{x} - (-frac{b}{x})}{1 + (-frac{a}{x})(-frac{b}{x})} right| = left| frac{frac{b - a}{x}}{1 + frac{ab}{x^2}} right| = left| frac{(b - a)x}{x^2 + ab} right| ] We need to maximize this expression.3. Maximize the Expression: Since we are maximizing (tan(angle ACB)), this is equivalent to maximizing (left| frac{(b - a)x}{x^2 + ab} right|).Let's implement this in Python using SymPy to find the coordinates of point (C):```pythonimport sympy as sp# Define variablesx = sp.symbols('x')a, b = sp.symbols('a b', positive=True, real=True)# Define the expression to maximize: (b - a)x / (x^2 + ab)expression = (b - a) * x / (x2 + a * b)# Find the critical points by taking the derivative and setting it to zeroderivative = sp.diff(expression, x)critical_points = sp.solve(derivative, x)# Evaluate the second derivative to confirm maximumsecond_derivative = sp.diff(derivative, x)# Filter critical points to find the one that maximizes the expressionmax_value = float('-inf')optimal_x = Nonefor point in critical_points: if point.is_real: if second_derivative.subs(x, point) < 0: value = expression.subs(x, point) if value > max_value: max_value = value optimal_x = pointprint(f"The coordinates of point C are: ({optimal_x}, 0)")``````outputTraceback (most recent call last): File " if second_derivative.subs(x, point) < 0:TypeError: cannot determine truth value of Relational```The error is occurring because SymPy cannot directly evaluate relational expressions (like inequalities) as True or False when they involve symbolic variables. To work around this, we can simplify our approach by considering the problem geometrically.We know that (angle ACB) is maximized when (C) is placed such that (angle ACB = 90^circ). This is because the right angle maximizes the angle between two vectors on the Cartesian plane.Given points (A(0, a)) and (B(0, b)), we need to place (C(x, 0)) such that (angle ACB = 90^circ). The perpendicularity condition can be achieved by ensuring that the dot product of vectors (overrightarrow{AC}) and (overrightarrow{BC}) is zero, since two vectors are perpendicular if and only if their dot product is zero.Let's set up this condition and solve for (x):1. Define Vectors: - (overrightarrow{AC} = (x, -a)) - (overrightarrow{BC} = (x, -b))2. Dot Product and Perpendicular Condition: - (overrightarrow{AC} cdot overrightarrow{BC} = 0)[ x cdot x + (-a) cdot (-b) = 0 ][ x^2 + ab = 0 ][ x^2 = -ab ]Since (x) must be real and positive, the only possible solution for (x) that maximizes (angle ACB) considering the Cartesian coordinate system is:[ x = sqrt{ab} ]Let's implement this solution in Python using SymPy:```pythonimport sympy as sp# Define variablesa, b = sp.symbols('a b', positive=True, real=True)# Define the optimal x based on the perpendicularity conditionx_optimal = sp.sqrt(a * b)# Print the coordinates of point Cprint(f"The coordinates of point C are: ({x_optimal}, 0)")``````outputThe coordinates of point C are: (sqrt(a)*sqrt(b), 0)```The coordinates of point (C) that maximize the angle (angle ACB) are:[Cleft( sqrt{a} cdot sqrt{b}, 0 right)]This can be further simplified as:[Cleft( sqrt{ab}, 0 right)]Thus, the coordinates of point (C) are:(boxed{left( sqrt{ab}, 0 right)})

question:Lily got a new puppy for her birthday. She was responsible for feeding the puppy 1/4 cup of food three times a day for two weeks starting tomorrow. For the following 2 weeks, Lily will feed him 1/2 cup of food twice a day. She has fed him 1/2 cup of food today. Including today, how much food will the puppy eat over the next 4 weeks?

answer:To calculate the total amount of food the puppy will eat over the next 4 weeks, including today, we'll break the problem down into smaller parts:1. Calculate the amount of food the puppy eats today.2. Calculate the amount of food the puppy eats in the first two weeks.3. Calculate the amount of food the puppy eats in the following two weeks.4. Sum up all these amounts to get the total. Step-by-Step Breakdown- Today: - Amount of food: ( frac{1}{2} ) cup- First 2 Weeks: - Number of days: 14 - Amount of food per day: ( frac{1}{4} ) cup * 3 times a day- Next 2 Weeks: - Number of days: 14 - Amount of food per day: ( frac{1}{2} ) cup * 2 times a dayWe then sum up all these amounts to get the total amount of food over 4 weeks.Let's use Python code to perform these calculations.```python# Amount of food fed todayfood_today = 1/2 # cups# Amount of food per day for the first 2 weeksfood_per_day_first_2_weeks = (1/4) * 3 # cupsdays_first_2_weeks = 14# Amount of food for the first 2 weeksfood_first_2_weeks = food_per_day_first_2_weeks * days_first_2_weeks # cups# Amount of food per day for the next 2 weeksfood_per_day_next_2_weeks = (1/2) * 2 # cupsdays_next_2_weeks = 14# Amount of food for the next 2 weeksfood_next_2_weeks = food_per_day_next_2_weeks * days_next_2_weeks # cups# Total amount of food over the 4 weeks including todaytotal_food = food_today + food_first_2_weeks + food_next_2_weeksprint(total_food)``````output25.0```The total amount of food the puppy will eat over the next 4 weeks, including today, is (boxed{25}) cups.

question:Susan, Arthur, Tom and, Bob are siblings. Arthur is 2 years older than Susan, and Tom is 3 years younger than Bob. If Bob is 11 years old, and Susan is 15 years old, how old are all four family members in total?

answer:To solve this problem, we will follow these steps:1. Assign Amy’s age: ( text{Susan's age} = 15 ) years.2. Determine Arthur’s age: Arthur is 2 years older than Susan. So ( text{Arthur's age} = text{Susan's age} + 2 ).3. Assign Bob’s age: ( text{Bob's age} = 11 ) years.4. Determine Tom’s age: Tom is 3 years younger than Bob. So ( text{Tom's age} = text{Bob's age} - 3 ).5. Finally, sum the ages of all four family members to get the total age.We will verify the calculations using Python code.Let's start by implementing this in Python:```python# Assign given agessusan_age = 15bob_age = 11# Calculate other agesarthur_age = susan_age + 2tom_age = bob_age - 3# Sum all agestotal_age = susan_age + arthur_age + bob_age + tom_ageprint(total_age)``````output51```The total age of all four family members (Susan, Arthur, Tom, and Bob) is (boxed{51}) years.

question:"That" and "this," plus half of "that" and "this" – how much will that be as a percentage of three-quarters of "that" and "this"?

answer:To solve this problem, we need to represent "that" and "this" as variables and then follow the given instructions:1. Define variables for "that" and "this".2. Compute ( text{"that"} + text{"this"} + frac{1}{2} (text{"that"} + text{"this"}) ).3. Compute three-quarters of ( text{"that"} + text{"this"} ).4. Find the percentage of the first result with respect to the second result.Let's implement this step-by-step in Python using the sympy library.```pythonimport sympy as sp# Define variablesthat, this = sp.symbols('that this')# Compute the first expression: that + this + 1/2 (that + this)first_expression = that + this + sp.Rational(1, 2) * (that + this)# Compute three-quarters of that + thissecond_expression = sp.Rational(3, 4) * (that + this)# Compute the percentage of the first expression with respect to the second expressionpercentage = (first_expression / second_expression) * 100# Simplify the final resultsimplified_percentage = sp.simplify(percentage)print(simplified_percentage)``````output200```The result shows that ( text{"that"} + text{"this"} + frac{1}{2} (text{"that"} + text{"this"}) ) is 200% of three-quarters of ( text{"that"} + text{"this"} ).Thus, the final answer is (boxed{200}).

question:Given the function f(x)= begin{cases} 3x- frac {1}{2}, & x<1 2^{x}, & xgeq 1 end{cases}, then f[f( frac {1}{2})] equals ______.

answer:To solve this problem, let's break it down into smaller steps:1. Understand the function ( f(x) ) and its piecewise definition: [ f(x) = begin{cases} 3x - frac{1}{2}, & x < 1 2^x, & x geq 1 end{cases} ]2. Compute ( fleft(frac{1}{2}right) ): Since (frac{1}{2} < 1), we use the first case of the piecewise function ( f(x) = 3x - frac{1}{2} ).3. Compute ( f left( fleft(frac{1}{2}right) right) ): Use the result of ( fleft(frac{1}{2}right) ) to determine which case of the piecewise function to use next.Let’s solve for ( fleft(frac{1}{2}right) ) first and then use the result to find ( fleft(fleft(frac{1}{2}right)right) ).Here's the step-by-step code to solve this:```pythonimport sympy as sp# Define the piecewise function f(x)x = sp.symbols('x')f_x = sp.Piecewise( (3*x - 0.5, x < 1), (2x, x >= 1))# Step 2: Compute f(1/2)x_val_1 = 1/2f_half = f_x.subs(x, x_val_1)# Step 3: Compute f(f(1/2))f_f_half = f_x.subs(x, f_half)# Evaluate the final resultresult = sp.simplify(f_f_half)print(result)``````output2.00000000000000```The value of ( f[fleft( frac{1}{2} right)] ) is (boxed{2}).

question:The base- 7 representation of number n is overline{abc}_{(7)} , and the base- 9 representation of number n is overline{cba}_{(9)} . What is the decimal (base- 10 ) representation of n ?

answer:To solve the problem, we need to find a number ( n ) such that its base-7 representation is (overline{abc}_{(7)}) and its base-9 representation is (overline{cba}_{(9)}).Let's denote the digits (a), (b), and (c) in the base-7 representation, where (a), (b), and (c) are integers between 0 and 6 (inclusive).Then the number ( n ) in decimal form can be represented from its base-7 form as:[ n = a cdot 7^2 + b cdot 7 + c ]Similarly, the number ( n ) in decimal form can be represented from its base-9 form as:[ n = c cdot 9^2 + b cdot 9 + a ]We need to find values of (a), (b), and (c) that satisfy both of these equations for (n).We'll write a Python function to iterate through possible values for (a), (b), and (c) and check when the two equations are equal.Let's implement this in Python.```python# Iterate through all possible values of a, b, and c in base-7 representationfor a in range(7): for b in range(7): for c in range(7): # Calculate n in decimal from base-7 representation n_base7 = a * 49 + b * 7 + c # Calculate n in decimal from base-9 representation n_base9 = c * 81 + b * 9 + a # Check if the two decimal values are equal if n_base7 == n_base9:print(( print(f'a: {a}, b: {b}, c: {c}, n: {n_base7}')))``````outputa: 0, b: 0, c: 0, n: 0a: 5, b: 0, c: 3, n: 248```We have found two solutions for (n):1. (a: 0, b: 0, c: 0) resulting in (n: 0)2. (a: 5, b: 0, c: 3) resulting in (n: 248)However, (n = 0) is trivial (it has no meaningful base-7 or base-9 structure other than zeros). The most relevant solution is:[ boxed{248} ]

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