Posted by Help101 on Sunday, June 17, 2012 at 9:02pm.
I need help with this problem: finding the instantaneous rate of change of y with respect to x at the point x=5 if y=x^2/2+3/5x1
I know I am suppose to find the determinant first then plug in 5...but I am not sure about the determinant

math  Reiny, Sunday, June 17, 2012 at 9:16pm
You meant "derivative" instead of "determinant"
The determinant has nothing to do with this.
dy/dx = x + 3/5
when x = 5
dy/dx = 5 + 3/5 = 28/5 or 5.6 
math  Help101, Sunday, June 17, 2012 at 9:23pm
wait, what happened to the 1?

math  Help101, Sunday, June 17, 2012 at 9:23pm
or the 2 in the x^2/2?

math  Help101, Sunday, June 17, 2012 at 9:25pm
...wait, duh, i figured out the x^2/2

math  Reiny, Sunday, June 17, 2012 at 9:47pm
I assumed you knew how to find the derivative of such a simple expression.
Remember the derivative of a constant is zero ,
if you want I could write it as
dy/dx = x +3/4 + 0 
math  Help101, Sunday, June 17, 2012 at 11:54pm
ohh okay, i forgot about that! thank u so much for helping me :)