I have a problem with c program calculation part . i have a mathematic funxion which equals to y. And i need to calculate the value. While x has a conditon thats value will increase 15 times. Like x1=a ; x2=a+h x3=a+h+(c*h) ; x4=a+h+(c*h)+((c*c)*h) ; x5=a+h+(c*h)+((c*c)*h)+((c*c*c)*h) and so on to X15. x1 which = A ,c,h and Ymin value is inserted by the program user. I Have come to conclusion , that i can write a formula for x value increase , which is Xi=Xi-1 +(c^i-2 * H) and it goes from x2 to x15 . My problem is that how i can write this to c language , what line i should write that the program would calculate x1 by just adding to the y= formula and from x2 to x15 it would use the condition that Xi=Xi-1 +(c^i-2 * H). And please dont give me just advice with this , i would just like to know how should i mark this in C language.