### Home > CALC > Chapter 3 > Lesson 3.1.2 > Problem 3-34

3-34.

In many textbooks the derivative (or IROC) is described in terms of

*x*and*∆x*(delta*x*) instead of*x*and*h.*Homework Help ✎

Explain why

*h*and ∆*x*are equivalent.Use the picture above and the definition of IROC to write the slope of the tangent line in terms of

*x*and ∆*x*.

Δ*x* can be translated as 'change in *x*.' *h* typically appears in the expression: (*x* + *h*) −*x*. How are these equivalent?

'Definition of the Derivative' is the same thing as 'Instantaneous Rate of Change': IROC