Tính: a) tích phân 0 3 |3 - x|; b) tích phân 0 2 (e^x - 4x^3); c) tích phân 0 pi/2 (sinx + cosx)
Giải thích
a) \(\int\limits_0^3 {\left| {3 - x} \right|dx} \) = \(\int\limits_0^3 {\left( { - x + 3} \right)dx} \) = \(\left. {\left( {\frac{{ - {x^2}}}{2} + 3x} \right)} \right|_0^3\) = \(\frac{{{3^2}}}{2} + 3.3 - \frac{{{0^2}}}{2} - 3.0\) = \(\frac{9}{2}\).
b) \(\int\limits_0^2 {\left( {{e^x} - 4{x^3}} \right)dx} \) = \(\left. {\left( {{e^x} - {x^4}} \right)} \right|_0^2\) = e2 – 24 – e0 + 04 = e2 – 17.
c) \(\int\limits_0^{\frac{\pi }{2}} {\left( {\sin x + \cos x} \right)dx} \) = \(\left. {\left( { - \cos x + \sin x} \right)} \right|_0^{\frac{\pi }{2}}\) = 2.