Can anyone please decipher the attached unit step functions? I am perplexed by some of the answers to questions set in fundamentals of electrical engineering, in particular the 'u(t-1) - 4t' in (a) and the use of t-u and t-u and u-t in (b). The final answers look OK but it's a mystery as to how they are arrived at. Thanks.

Neil Tetlow

 

Hello there
Is this homework?

Wow. A reply. No it's not homework. I'm way over that. Just wondered if anyone could decipher that stuff for me.
Thanks