P$12\mathrm{.}01$b$\_6$ed

Use step functions to write the expression for this waveform.

a$)$ Write the expression for the interval $-4<=$ t $<=0$ sec$.$

f$($t$)=(30$ t $+120)[$u$($t $+$ Answer $1$ Question $5)$ u$($t $-$ Answer $2$ Question $5)]$

b$)$ Write the expression for the interval $0<=$ t $<=8$ sec$.$

f$($t$)=(-30$ t $+120)[$u$($t $$ Answer $3$ Question $5)$ u$($t $-$ Answer $4$ Question $5)]$

c$)$ Write the expression for the interval $8<=$ t $<=12$ sec$.$

f$($t$)=(30$ t $-360)[$u$($t $$ Answer $5$ Question $5)$ u$($t $-$ Answer $6$ Question $5)]$