YLL討論網

toadfadfadf 寫到:#ed_op#div#ed_cl#請教一題積分  我在某個地方的觀念有點卡住#ed_op#br#ed_cl#                                                                                #ed_op#br#ed_cl#   1#ed_op#br#ed_cl# ∫   cos(2πft+π) cos(2πft) dt#ed_op#br#ed_cl#   0#ed_op#br#ed_cl#                                                                                #ed_op#br#ed_cl#         1#ed_op#br#ed_cl#=  1/2 ∫    cos(π) + cos(4πft + π) dt#ed_op#br#ed_cl#         0#ed_op#br#ed_cl#                                                                                #ed_op#br#ed_cl#= - 1/2#ed_op#br#ed_cl#                                                                                #ed_op#br#ed_cl#                                                                                #ed_op#br#ed_cl#                                                                                #ed_op#br#ed_cl#                                                                                #ed_op#br#ed_cl#我想問的是#ed_op#br#ed_cl#                                                                                #ed_op#br#ed_cl#  1#ed_op#br#ed_cl#∫   cos(4πft + π)  dt   =  0#ed_op#br#ed_cl#  0#ed_op#br#ed_cl#                                                                                #ed_op#br#ed_cl#                                                                                #ed_op#br#ed_cl#這種積分是要怎麼積呢 ?#ed_op#br#ed_cl##ed_op#/div#ed_cl##ed_op#div#ed_cl#要考慮 π  還是不用考慮 π#ed_op#br#ed_cl#                                                                                #ed_op#br#ed_cl#如果要考慮π的話  答案應該不是 0 才對#ed_op#br#ed_cl#                                                                                #ed_op#br#ed_cl#要怎麼推出答案是 0 的結果#ed_op#br#ed_cl#                                                                                #ed_op#br#ed_cl#希望有好心人解答一下#ed_op#br#ed_cl#                                                                                #ed_op#br#ed_cl#謝謝  ^^#ed_op#br#ed_cl##ed_op#/div#ed_cl##ed_op#div#ed_cl# #ed_op#/div#ed_cl##ed_op#div#ed_cl##ed_op#/div#ed_cl##ed_op#div#ed_cl##ed_op#/div#ed_cl##ed_op#div#ed_cl##ed_op#/div#ed_cl#

#ed_op#br#ed_cl##ed_op#br#ed_cl#  1#ed_op#br#ed_cl#∫   cos(4πft + π)  dt#ed_op#br#ed_cl#  0#ed_op#br#ed_cl#    1#ed_op#br#ed_cl#=∫   cos( (4ft+1)π )  dt   =  0,  if f∈#ed_op#span style="font-weight: bold; font-style: italic;"#ed_cl#Z#ed_op#/span#ed_cl##ed_op#br#ed_cl#    0#ed_op#br#ed_cl##ed_op#br#ed_cl#因為 ∫ cos( uπ ) du =0, , f∈#ed_op#span style="font-weight: bold; font-style: italic;"#ed_cl#Z#ed_op#/span#ed_cl#

#ed_op#DIV#ed_cl#請教一題積分  我在某個地方的觀念有點卡住#ed_op#BR#ed_cl#                                                                                #ed_op#BR#ed_cl#   1#ed_op#BR#ed_cl# ∫   cos(2πft+π) cos(2πft) dt#ed_op#BR#ed_cl#   0#ed_op#BR#ed_cl#                                                                                #ed_op#BR#ed_cl#         1#ed_op#BR#ed_cl#=  1/2 ∫    cos(π) + cos(4πft + π) dt#ed_op#BR#ed_cl#         0#ed_op#BR#ed_cl#                                                                                #ed_op#BR#ed_cl#= - 1/2#ed_op#BR#ed_cl#                                                                                #ed_op#BR#ed_cl#                                                                                #ed_op#BR#ed_cl#                                                                                #ed_op#BR#ed_cl#                                                                                #ed_op#BR#ed_cl#我想問的是#ed_op#BR#ed_cl#                                                                                #ed_op#BR#ed_cl#  1#ed_op#BR#ed_cl#∫   cos(4πft + π)  dt   =  0#ed_op#BR#ed_cl#  0#ed_op#BR#ed_cl#                                                                                #ed_op#BR#ed_cl#                                                                                #ed_op#BR#ed_cl#這種積分是要怎麼積呢 ?#ed_op#BR#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl#要考慮 π  還是不用考慮 π#ed_op#BR#ed_cl#                                                                                #ed_op#BR#ed_cl#如果要考慮π的話  答案應該不是 0 才對#ed_op#BR#ed_cl#                                                                                #ed_op#BR#ed_cl#要怎麼推出答案是 0 的結果#ed_op#BR#ed_cl#                                                                                #ed_op#BR#ed_cl#希望有好心人解答一下#ed_op#BR#ed_cl#                                                                                #ed_op#BR#ed_cl#謝謝  ^^#ed_op#BR#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl# #ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#/DIV#ed_cl##ed_op#DIV#ed_cl##ed_op#/DIV#ed_cl#