Tính các tích phân sau: a) 3 ∫ 1 e x − 2 d x ; b) 1 ∫ 0 ( 2 x − 1 ) 2 d x ; c) 1 ∫ 0 e 2 x − 1 e x + 1 d x .
a) \[\int\limits_1^3 {{e^{x - 2}}dx} = \int\limits_1^3 {\frac{{{e^x}}}{{{e^2}}}dx} \]
\[ = \left. {\frac{{{e^x}}}{{{e^2}}}} \right|_1^3 = \frac{{{e^3}}}{{{e^2}}} - \frac{e}{{{e^2}}} = e - \frac{1}{e}\].
b) \[\int\limits_0^1 {{{\left( {{2^x} - 1} \right)}^2}dx} = \int\limits_0^1 {\left( {{4^x} - {{2.2}^x} + 1} \right)dx} \]
\[ = \left. {\left( {\frac{{{4^x}}}{{\ln 4}} - 2.\frac{{{2^x}}}{{\ln 2}} + x} \right)} \right|_0^1\]
\[ = 1 - \frac{1}{{2\ln 2}}\].
c) \[\int\limits_0^1 {\frac{{{e^{2x}} - 1}}{{{e^x} + 1}}dx} = \int\limits_0^1 {\frac{{\left( {{e^x} + 1} \right)\left( {{e^x} - 1} \right)}}{{{e^x} + 1}}dx} \]
\[ = \int\limits_0^1 {\left( {{e^x} - 1} \right)dx = \left. {\left( {{e^x} - x} \right)} \right|_0^1 = e - 2} \].