### Home > CALC > Chapter Ch5 > Lesson 5.1.1 > Problem 5-7

5-7.

*f* ''(*x*) tells us the same thing about *f* '(*x*) that *f* '(*x*) tells us about *f*(*x*).

*f* '(*x*): 3*x*² + 6*x* −9*f* ''(*x*): 6*x* + 6

Consider this: Even though a slope of −2 is steeper than a slope of −1, if the slope changes from −1 to −2, then the slope is decreasing.

Positive values of the 2nd-derivative indicate that the function is concave up while negative values indicate that the function is concave down.