- #1
Poirot
- 94
- 2
Homework Statement
y= A(x-sin(x)) with A as a constant.
Homework Equations
dy/dx = A(1-cos(x)) ??
The Attempt at a Solution
If I am thinking about this correctly, one can just differentiate the function as I have, and argue that when the gradient (dy/dx) is less than zero, the function is decreasing. So from this:
A(1-cos(x))<0
so 1-cos(x)<0
cos(x)>1
which never happens for any x, including negative x since cos is an even function.
Is this the right way of doing this? I'm very rusty on proofs etc.
Thanks in advance!