Search results

Yep, as the mathematics you used to attain either answer is correct, as you rounded to 2 sig figs, and they didn't specify to use the rounded value of k in part iii, i.e., through using the directive 'hence', etc. Essentially, if the method's correct, they'll accept the solution, especially...

whereabouts is the paper?

Yep

No, you just had to show that x=3.75 was a minimum through either showing d^2y/dx^2>0, or through showing the gradient was <0 for values <3.75, and >0 for values greater 3.75.

x=15/4=3.75