分からない問題はここに書いてね435

>>76

exp(x/c) = 1 + x/c + (1/2)*(x/c)^2 + o((x/c)^2) (c → ∞)
exp(-x/c) = 1 - x/c + (1/2)*(x/c)^2 + o((x/c)^2) (c → ∞)

exp(x/c) + exp(-x/c) = 2 + (x/c)^2 + o((x/c)^2) (c → ∞)

{exp(x/c) + exp(-x/c)}/2 = 1 + (1/2)*(x/c)^2 + o((x/c)^2) (c → ∞)

{exp(x/c) + exp(-x/c)}/2 - 1 = (1/2)*(x/c)^2 + o((x/c)^2) (c → ∞)

{[{exp(x/c) + exp(-x/c)}/2 - 1] - (1/2)*(x/c)^2}/(1/c^2) = o((x/c)^2)/(1/c^2) (c → ∞)

{[{exp(x/c) + exp(-x/c)}/2 - 1] - (1/2)*(x/c)^2}/(1/c^2) = 0 (c → ∞)

c^2*{[{exp(x/c) + exp(-x/c)}/2 - 1] - (1/2)*(x/c)^2} = 0 (c → ∞)

c^2*[{exp(x/c) + exp(-x/c)}/2 - 1] - (1/2)*x^2 = 0 (c → ∞)

c^2*[{exp(x/c) + exp(-x/c)}/2 - 1] = (1/2)*x^2 (c → ∞)