Is it even possible to work this out? | Boarding School Entrance Problem

[@amaay1498]

Hi just to want to test your knowledge, can you solve this question: If f(x) is a differentiable function and g(x) is a double differentiable function such that If(x) | ≤ 1 and f'(x) = g(x). If f^2(0) + g^2(0) = 9. Prove that there exists some C € (-3, 3) such thatg(c). g"'(c) < 0.

[@eternity_hour]

If f(x) = sin(3x), g(x) = 3cos(3x), g”(x) = -27cos(3x), if c = 0, g”(x) = -27, which is less than zero.

[@tahmidhassan1088]

i hope edexcel dont take inspiration for gcse paper 3....

[@eternity_hour]

Pretty unlikely, though part of me wishes that each paper ended with a bonus question like this one