Answer to question 2.2.8 all unsolved parts

Answer to 2.2.8 (e)

Differentiating this using quotient rule and chain rule, we get :

Now we need to use this result for simplifying the above differential :

From these two properties, sinh(bx)-cosh(bx) can be written as(This is obtained by simply subtracting) :

 

 So by replacing, our derivative is simplified as follows :  

NOTE : The answer given at the end of the book is wrong. The one above is correct.