Question

verify that y_1 = e^x; y_2= cosh(x) and y_3= sinh(x) are solution of y"'-y"-y'+y=0
I got y_1. I got stuck at y_2
Please help

Answer 1

my work for y_2 is
y= cosh(x)
y'= -sinh(x)
y" = -cosh(x)
y"'= sinh(x)
so, sinh(x)-(-cosh(x))-(-sinh(x)) +cosh(x)= 2sinh(x) +2cosh(x) \(\neq\)0

Answer 2

What's wrong with my stuff?

Answer 3

http://www.wolframalpha.com/input/?i=d%2Fdx++cosh(x)

How about this?

Answer 4

oops!! let me check on my note. hehe, just did by my bad memorize

Answer 5

Thank you very much,