error:Call of nonfunction in function main()

[situ]

#include<stdio.h>
#include<conio.h>
#include<math.h>
#include<string.h>
void main()
{
int i=0;
float A=0,B=0;
float p2=0,p3=0,c2=0,c3=0,b=0,R2=0;
float w[10]={1e2,1e4,1e6,1e8,1e10,1e12,1e14,1e16,1e18,1e20};
float p2e[10];
printf("enter the value of p2,p3,c2,c3,b,R2");
scanf("%f %f %f %f %f %f %f" ,&p2,&p3,&c2,&c3,&b,&R2);
{
for (i=0;i<10;i++)
{
A=p2*R2((p3*((R2*p2)+(b*p3)))+(b*(c3/w[i])*(c3/w[i]))); (error:Call of nonfunction in function main() occur in this line)
B=(((R2*p2)+(b*p3))*((R2*p2)+(b*p3)))+((c3*(b/w[i]))*(c3*(b/w[i])));
p2e[i]=A/B;

}
for (i=0;i<10;i++)
printf("%f",p2e[i]);
printf("\n");
} }





plz help me to solve this error

[donbock]

A=p2*R2((p3*((R2*p2)+(b*p3)))+(b*(c3/w[i])*(c3/w[i])));

The first instance of R2 is immediately followed by a parenthesized expression. The compiler assumes your desire is to call R2 and pass it the value of the expression. However, R2 is not a function so you get the error.