Number Formate

 -(NSString *)stringFromNumber:(NSNumber *)number
    {
        NSLog(@"Input:---%@",number);
        NSNumberFormatter *numFormatter = [[[NSNumberFormatter alloc] init] autorelease];
        [numFormatter setMaximumFractionDigits:5];
        [numFormatter setMinimumFractionDigits:2];
        //[numFormatter setExponentSymbol:@"e"];
        NSString *str_num = [numFormatter stringFromNumber:number];
        NSLog(@"Output:---%@",str_num);
        return str_num;
    }
        in console i am getting like below
    Input:---2.940000057220459
    Output:---2.94
    Input:---2940.000057220459
    Output:---2940.00006
    Input:---2.940000057220459e-15
    Output:---.00
    Input:---2.940000057220459e-12
    Output:---.00
    Input:---2.940000057220459e-09
    Output:---.00
    Input:---2.940000057220459e-06
    Output:---.00
    Input:---0.002940000057220459
    Output:---.00294
but i need like below for above inputs (order)
---2.94
---2940
---2.94e-15
---2.94e-12
---2.94e-6
---2.94e-9
---0.00294