Slope of tangent when $|f(x_1)-f(x_2)|\leq(x_1-x_2)^2$ for all $x_1,x_2 \in R$ If $|f(x_1)-f(x_2)|\leq(x_1-x_2)^2$ for all $x_1,x_2 \in R$, then find the slope of tangent to the curve at $y=f(x)$ at the point $(1,2)$.

Could someone hint me as how to approach this question. Is data sufficient to find the required slope?
I hope this helps. Next time, learn your definitions
I hope this helps. Next time, learn your definitions