## Derivative - mathematics : Solution of exercise 1

Basic level

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Find the slope of a straight line graphically and, knowing the equation *y = (-1/3)x + 1*, compare the value of the derivative *y'* to the slope.

**a) Slope of the straight line calculation**

Slope of the line =

**b) Derivative ***y '* of the straight line

**c) Reach a conclusion on the result obtained in a) and b)**

The slope of the line, computed in a), is equal to the derivative of the straight line equation, computed in b). Indeed, the derivative of a linear function (general equation of a linear function : ) equals the slope of the line described by that function. In other words, the derivative of a linear function is the angular coefficient *a* of the function.

Calculate a derivative is the same than calculate a slope and inversely.