There are some systems in which only real and positive values can be transmitted. in the following matlab example, we show 3 systems. system 1 is the ordinary ofdm system and no special constraint is applied. system 2 follows conjugate symmetry property to ensure real value ifft output. system 3 also follows conjugate symmetry property. in addition, all odd-index values of x3 are set to 0. the output of ifft, x3, are real but can be both positive and negative. the transmitter simply sets the negative part of x3 to be 0 so that x3 p is resulted. it is clear that x3_p is real and positive. however, can the receiver recover x3 from x3_p? how and why? complete theoretical derivation/proof and matlab code.

1. web and mobile applications allow users to be actively engaged in an online activity. a true b false 2. some examples of business applications purposes are to collaborate, share files, meet virtually in real-time, and accept payments. a true b false 3. an education application would most likely do which of the following? a allow users to watch popular movies and tv shows b connect users with social and business contacts c confirm users' travel plans d teach users a new language 4. a uniform resource locator (url) is how the internet knows where to take users when an address is typed into a browser. a true b false 5. deon is required to provide the citation information for his sources. what type of information should he collect from his sources? a author name, title, date of publication, date of access, url b connections to background information c interesting facts and statistics d notes on important information