We basically have to find the places where the slope of tangent line is
negative, 0 , and positive.
That is, taking the derivative of the function and graphing that.
Wherever that is negative, 0 , and positive, that is our answer.
The function is:
Derivative is:
Graph of the function "2x" (line):
As u can see,
Positive
x < 0
Zero
at x = 0
Negative
x > 0