Mr and Mrs Davis have a son. His name is Bobby, and it was his birthday a few days ago.
Last Sunday Bobby's grandfather came to visit them, and he brought Bobby a nice toy train. When he gave it to Bobby, he said: "I'm sorry, Bobby, but I forgot your birthday last Tuesday, so I give you this present then."
"Oh, that doesn't matter Grandpa," Bobby answered. "Thank you very much. It's just what I wanted."
"And how old are you now, Bobby?" his grandfather asked. Bobby knew the answer to that question. "I'm five, Grandpa," he said.
"That's good," the old man said. "You're a big boy now, Bobby. And what are you going to be when you're older?" Bobby knew the answer to that question, too. "I' m going to be six, Grandpa," he answered
Этот?
Найдём тотку пересечения графика и касательной:
x^3 + 4x^2 + 3x + 4 = 3x + 4
x^3 + 4x^2 = 0
x^2 * (x + 4) = 0
x = 0 или x = -4.
у = 3х + 4 = 3 или y = -8
Имеем две точки: (0; 3) и (-4; -8)
Точка касания должна принадлежать графику производной:
y' = 3x^2 + 8x + 3.
Точка (0; 3) принадлежит этому графику.
Точка (-4; -8) не принадлежит этому графику.
ответ: абсцисса равна 0.