Kofi’s eyes widened. He pulled out his phone and opened the PDF. At the bottom of the first page, a new line had appeared:
Kofi almost fell off his chair. “Who—what are you?” Godman-Additional-Mathematics-For-West-Africa-Pdf.pdf
He stepped back into the phone screen, and the room cooled. The PDF now showed a normal cover page: Godman-Additional-Mathematics-For-West-Africa , with chapters on calculus, statistics, and mechanics. Kofi’s eyes widened
As he spoke, chalk lines appeared in the air: [ f'(x) = \lim_{h \to 0} \frac{f(x+h) - f(x)}{h} ] with chapters on calculus
Kofi, too stunned to argue, pointed at a question: Find the derivative of f(x) = 3x² + 2x from first principles.