分からない問題はここに書いてね453

(-1/2) * exp(-(k + 1) * π) * (sin((k + 1) * π) + cos((k + 1) * π))

-

(-1/2) * exp(-k * π) * (sin(k * π) + cos(k * π))

=

(-1/2) * exp(-(k + 1) * π) * cos((k + 1) * π)

-

(-1/2) * exp(-k * π) * cos(k * π)

=

(-1/2) * exp(-(k + 1) * π) * (-1)^(k + 1)

-

(-1/2) * exp(-k * π) * (-1)^k

=

(1/2) * exp(-(k + 1) * π) * (-1)^k

+

(1/2) * exp(-k * π) * (-1)^k

=

(-1)^k * (1/2) * (exp(-(k + 1) * π) + exp(-k * π))

∴

S_k

=

| (-1)^k * (1/2) * (exp(-(k + 1) * π) + exp(-k * π)) |

=

(1/2) * (exp(-(k + 1) * π) + exp(-k * π))