Recent content by shar_p

Ok I think I get it. I need to go from f(x) to f'(x3) first before substituting g and that is what is confusing my friend.

But I still don't understand why we have to use {f(x3)}'' and not f''(x3). since f' = g f'(x3) = g(x3) f''(x3) = 3x2 g'(x3) = 3x2f(x6)

I tried to explain this to my friend and he said that : if d/dx(f(x)) = g(x) and d/dx(g(x)) = f(x2), then d2/dx2 ( f(x3) ) = ? since d/dx(g(x)) = d2/dx2(f(x)) = f(x2) , d2/dx2(f(x3)) = f((x3)2)=f(x6) so my initial step of (f(x3))' would be 3 x2 g(x3) is wrong? since f' = g f'(x3) = g(x3)...

g'(x) = f(x2), so g'(x3) = f((x3))2 = f(x6) and so (g(x3))' = … ? ans = 6x.g(x3) + 3x2. (g(x3))' = 6x.g(x3) + 3x2.f(x6).3x2 = 6x.g(x3) + 9x4.f(x6) yes! Thanks a lot.

Thanks for the hints: f' = g so (f(x3))' would be 3 x2 g(x3) But we need d2/dx2(f(x3)) which is ( 3 x2 g(x3) )' = 6x.g(x3) + 3x2. (g(x3))' How do I simplify it further? what is (g(x3))' ? I guess since this is a multiple choice question and 1 of the answers is 9x4f(x6) + 6x g(x3)...

Homework Statement if d/dx(f(x)) = g(x) and d/dx(g(x)) = f(x^2), then d^2/dx^2 ( f(x^3) ) = ? Homework Equations The Attempt at a Solution from 1 and 2 we get d.dx(g(x)) = d2/dx2(f(x)) = f(x^2) but then what? That doesn't tell me anything about f(x^3) Please help.

Thanks .. that worked.

Homework Statement The exhaust temperature of a Carnot heat engine is 401◦ C. What is the intake temperature if the efficiency of the engine is 40.2 %? Answer in units of ◦ C. Homework Equations e = 1 - Tc/Th (all in Kelvin) The Attempt at a Solution 0.402 = 1 - Tc/ (401+273) = 1...

Thanks. Since the wo is the same for the metal the one found in 1st case can be used in the 2nd case. Thanks much.

E = [(6.67x10^-34)(3.0x10^8)]/4.5x10^-7 = 4.446x10-33 since KE = 3.2x10^-19, wo = -3.2x10^-19 Enew = [(6.67x10^-34)(3.0x10^8)]/6.8x10-7 = 2.94 x 10^ -33 since wo is negative, though mag of E is smaller than Wo, E > wo and so there will be emission. I got these answers but the answer specified...

Homework Statement Monochromatic light of wavelength 4.5 x 10-7 m will eject electrons from the surface of a metal with a maximum KE of 3.2 x 10-19 Joules. Will light having a wavelength of 6.8 x 10-7 m also cause emission of electrons from this metal Homework Equations E = h.c/lambda...

Thanks for the reply. rl.bhat thanks for catching my silly mistake. Glad this problem was not on the test. Though I don't agree with Doc Al that the sign -Fpy is wrong in Sum of Fy = Fn - Fpy - Fgy = 0 because Fpy is downward because the Fp is pushed up the ramp and because of that Fn =...

Homework Statement I have a test on this tomorrow .. please help.. A box, initially at rest, is pushed up a ramp by a constant force acting 20 degrees above the ramp’s surface (pushing into the ramp from behind the box). The magnitude of the force is 50.0 N. The coefficient of friction is...

Homework Statement A penny sits at the bottom of a pool of water (n=1.33) at a depth of 3.0m. If the observer 1.8m tall stands 30cm away from the ledge, how close to the side can the penny be and still be visible to the observer. Suppose there is another penny 10 times farther away than the...