《数学分析课后习题答案--高教第二版(陈纪修)--16章》.pdf

m E (t ) A sin ωt o 16.1.5(a) c A (a). ( ) (sin f 1 t ωt +|sin ωt | ) 2 w 16.1.5(b) a f 2 (t ) A |sin ωt | d ω 1 f 1(x ) f 2 (x ) h (b) [ , ]−π π Fourier a 1 π ( ) 2A k 0 π ∫−π f 1 x dx π . 1 π 2A a f (x )cosnxdx =− n 2, 4,6, w n π ∫−ππ 1 π(n2 −1) w 1 an ∫−π f 1(x ) cosnxdx 0 n 1,3,5, π w 1 π A b f x xdx 1 ∫−π 1( )sin π 2 网 1 π bn ∫−π f 1(x )sinnxdx 0 n 2,3, 4, π 案 A A 2A ∞ cos 2kx 答 f 1(x ) ∼ + sin x − ∑ 2 后 π 2 π k 1 4k −1 1 π 4A a 课 ( ) 0 ∫−π f 2 x dx π π 1 π 4A an π ∫−π f 2 (x )cosnxdx =−π(n2 −1) n 2, 4,6, … 1 π an ∫−π f 2 (x )cosnxdx 0 n 1,3,5,… π 1 π bn ∫−π f 2 (x )sinnxdx 0 n 1, 2,3, π 2 A 4 A cos 2kx ∞ f 2 (x ) ∼ − ∑ 2 π π 4 k 1 1k − Fouri