What is the slope of the secant line between the points $x=3.1$ And $x=3$ given is $f(x)=\sin(2x)$

Question

Should I replace $x$ in $\sin(2x)$ by $3.1$ and after that will be replaced by $3$? I tried to compute but the result is $0$. What do I need to do to solve the slope of the secant line of the equation $f(x)=\sin(2x)$ between the points $x=3.1$ and $x=3$.

Please help.

Answer 1

the slope will be simply $ \frac{sin(6.2) - sin(6)}{3.1 - 1} = 1.9632 $ and not zero

Answer 2

Slope $m = \dfrac{\sin(2\cdot 3.1) - \sin(2\cdot 3)}{3.1-3}=...$, and you are in radian mode when using the calculator.