[填空题]
A toy racing car is ,pz (n (i(tybzdm,n)owp c5 a,s(hfery5v- ,hrx,jq+iriving over a hill on a path that can be modelled by part of the funct ) e5+qw,cnrh hyx5i vm(raoj,f ,sp-,ion
f(x)=-$\frac{1}{4}x^2+5$.
1.Find the gradient of the hill at the point where x=2.
f'(2)=- .
2.Find the x value of the point where the gradient perpendicular to the hill is equal to $\frac{3}{2}$.
the number is $\frac{a}{b}$ ,a= , b= .
