q*L^4/8AB-R*L^3/3AB=R/(AB/L^3) 如何算出R=3qL/2?

Answer 1

最佳解答

Sol

QL^4/(8AB)－R*L^3/(3AB)=R/(AB/L^3)

QL^4/(8AB)－R*L^3/(3AB)=RL^3/(AB)

(24AB/L^3)[Q*L^4/(8AB)－R*L^3/(3AB)]=(24AB/L^3)RL^3/(AB)

24[QL/8－R/3]=24R

3QL－8R=24R

3QL=32R

R=3QL/32

Answer 2

Q(L^4)/(8AB)-R(L^3)/(3AB)=R/(AB/L^3)

3Q(L^4)/(24AB)-8R(L^3)/(24AB)=R(L^3)/(AB)

[3Q(L^4)-8R(L^3)]/24=R(L^3)

3QL-8R=24R

3QL=32R

R=3QL/32

Answer 3

Q*L^4/8AB-R*L^3/3AB = R/(AB/L^3)

Q*L^4/8AB = R*L^3/AB +1/3(R*L^3/AB)

Q*L^4/8AB = 4/3(R*L^3/AB)

L^3/AB(Q*L/8) = L^3/AB(4/3)R

Q*L/8 = (4/3)R

∴ R=3QL/32

# [你的答案：R=3qL/2 , 是 分母漏了個 3 字嗎?]