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| 所有積分大於負-100的壞孩子,將可獲得重新機會成為懲罰生,權限跟幼兒生一樣。 let P+m-kt = x
dv/dt = dv/dx * dx/dt = dv/dx * -k
=> -kx * dv/dx = ck - xg
dv= (xg-ck)/(kx) dx = ( g/k - c/x ) dx
v=gx/k - c ln(x) + C
v=g(P+m-kt)/k - c ln(P+m-kt) + constant
v(0) = g(P+m)/k - c ln (P+m) + constant = 0
constant =c ln (P+m) - g(P+m)
v(t) = -gt - c ln(1-kt/(P+m))
vt = v(epsilon * m/k) = -g(epsilon *m/k) - c ln(1-epsilon*m/(m+P))
=>vt= - c ln(1-epsilon*m/(m+P)) - g* epsilon *m/k ... |
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