Combined Math Solutions (Hybrid Vehicle & Logarithmic Problems)
Part 1: Hybrid Vehicles Sales Analysis
Given data: x = [1, 2, 3, 4, 5, 6], y = [18, 32, 65, 84, 105, 123]
Regression Line Equation: y = 21.80x + -5.13
Center of Gravity G = (3.50, 71.17)
Correlation Coefficient r = 0.9953
Estimate for 2022 (x = 7): y = 147.47 thousand vehicles
Actual (15% increase from 2021): y = 141.45 thousand vehicles
Percentage Relative Error = 4.25%
Part 2: Logarithmic and Calculus Problems
1) Domain of f(x) = x / (1 - ln(x))
To be defined, ln(x) must exist => x > 0
Also, denominator != 0 => 1 - ln(x) != 0 => ln(x) != 1 => x != e
Final Domain: (0, e) U (e, infinity)
2) Derivative of f(x) = ln(2x - 1) - ln(2x + 1)
Using d/dx ln(u) = u'/u:
f'(x) = (2)/(2x - 1) - (2)/(2x + 1)
3) Solve ln(x + e) = 1
x + e = e^1 = e => x = 0
4) Solve inequality e^x + 4 > 1
e^x > -3 which is always true since e^x > 0
So solution set is all real numbers R