1. (a) 30
    (b)  24n^3+156n^2+322n
2. [(a+1)(b^2+c^2-6)]/2(c^-1)^0.5
3. (a) 4/(n^2-1)
    (b) 4(n^2-5)/[(n^2-1)(n^2-2)]
4. 2-4/파이