equation with several variation

hello everybody im new here and try to learn Mathcad im struggling with an equation, somedays I keep working and asking and already I lean a lot I wrote an equation which  attached  here and  put an screenshot ,  there are value of I with different interval but what I  need now to solve and compare this equation with different value of R also  it means R has 3 different value 0.35 , 1.5, 3.5,4.7 as you see in picture each I shown with specific interval but R is fixed value