Solving Control System Problem: Finding Maximum Velocity Error Constant (Kv)

[gholamghar]

Homework Statement

question:
find maximum velocity error constant(K_v)
feedback is :1 positive

the book says the right answer is:0.75

but every time i calculate E(s) it goes to the wrong answer!
please help!

 

[CEL]

Kv is K/2. The book's answer is correct if K = 1.5.

 

[gholamghar]

thanks for the reply it helped a lot.