"Still stuck?" a voice whispered. It was Lena, the class's resident math wizard.
The fluorescent hum of the library was the only sound as Mark stared at the worn cover of his textbook. Chapter 4, "Trigonometric Functions," felt like a wall he couldn't climb. koliagin gdz 10 klass
Lena didn't reach for her calculator. Instead, she pulled up a familiar bookmark on her phone: the for Kolyagin. She didn't just show him the answer; she scrolled through the step-by-step breakdown. "Still stuck
