Please solve the following problem. Do not copy any answers from Chegg. The problem must be uniquely answered. Thank you $4\mathrm{.}8$ A double cantilever simply supported beam $($Fig$.$ P$4\mathrm{.}8)$ supports in addition to its weight a live load of $80$ psf and a concentrated load at its ends $($as shown$)$ of $750$ lb$.$ This concentrated load can be considered as a dead load due to the weight of a wall. The following information is given: $[$ f$\_$c$^\text{'}=5000$ psi ; f$\_$c i$^\text{'}=4000$ psi ; f$\_$r$=-7\mathrm{.}5($f$\_$c$^\text{'})$ ; $\backslash$gamma $\_$c$=150$ pcf ;; $\backslash$sigma $\_$t i$=-189$ psi ; $\backslash$sigma $\_$c i$=2400$ psi ; $\backslash$sigma $\_$t s$=-213$ psi ; $\backslash$sigma $\_$c s u s$=2250$ psi ; $\backslash$sigma $\_$c s$=3000$ psi ;; $\backslash$eta $=0\mathrm{.}80$ ;$($d$\_$c$)\_$min$=3$ in ; f$\_$p u$=270$ ksi ; f$\_$p e$=150$ ksi ; area of one strand $=0\mathrm{.}153$ in$^2.]($a$)$ Determine the required value of the prestressing force to be used throughout the length of the beam $($i$.$e$.,$ check F at A$,$ F at B$,$ and select the largest value; then check that all stresses are satisfied$).$ Think about using the feasibility domain for solution. Select F corresponding to an integer number of strands. $/$r$/$n $($b$)$ Determine the upper and lower limits of the steel envelopes at support, midspan, quarter span, end D$,$ and $5$ ft from D $($i$.$e$.,$ E $).($c$)$ Plot graphically the limit zone and show an acceptable profile for the prestressing force. b Figure P$4\mathrm{.}8$