Solve Calculus Problem: f'(x)g'(x) = xf'(x)+f(x) | 10th Fri

  • Thread starter Thread starter unrealplayer
  • Start date Start date
  • Tags Tags
    Calculus
AI Thread Summary
The discussion focuses on solving a calculus problem involving the derivative of the function g(x) = xf(x). Participants are asked to use the definition of a derivative to demonstrate that g'(x) equals xf'(x) + f(x). The definition of a derivative is provided to guide the solution process. The urgency of the request is emphasized, with a deadline set for Friday the 10th. The original poster expresses gratitude for any assistance received in solving the problem.
unrealplayer
Messages
2
Reaction score
0
If you can work this out please try and reply to it before friday the 10th!



#1: If f is a differentiable function and g(x) = xf(x), use the
definition of a derivative to show that g'(x)(g prime of x) =
xf'(x)+f(x)(xf prime of x plus f of x).

Definition of a Derivative:

The Derivative of a function f at a number a, denoted by
f'(a) (f prime of a), is:

Lim f(a + h) - f(a)
x -> 0 --------------
h​
 
Physics news on Phys.org
Apply the definition directly to g(x).
 
Thanks a lot, I found/got the right answer
 
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Thread 'Variable mass system : water sprayed into a moving container'
Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
Back
Top