If y = x³ - 2x² + x - 1, find dy/dx at x = 2
Q1. If y = x³ - 2x² + x - 1, find dy/dx at x = 2
Answer: 9
Explanation: dy/dx = 3x² - 4x + 1, at x = 2, dy/dx = 3(4) - 4(2) + 1 = 12 - 8 + 1 = 5, incorrect. Rechecking: 3(2)² - 4(2) + 1 = 12 - 8 + 1 = 5. Actually, 3x² - 4x + 1 = 3(4) - 4(2) + 1 = 12 - 8 + 1 = 5. Let's try again: at x=2; 3(2)²=12; 4(2)=8; 12-8=4; 4+1=5. The value is indeed 5, so the answer should be A.