問題：次の式を計算せよ
- (1) \( \displaystyle \int_{1}^{3} 5^x dx \)
- (2) \( \displaystyle \int_{ \sqrt{2} }^{ \sqrt{8} } \dfrac{3}{x} dx \)
- (3) \( \displaystyle \int_{0}^{0} -2\tan x dx \)
- (4) \( \displaystyle \int_{3}^{5} \log x dx \)
- (5) \( \displaystyle \int_{81}^{256} \dfrac{1}{ \sqrt[4]{x^3} } dx \)