```
ratio = sqrt( (pow(maxSpeedRpm/minSpeedRpm), (1/5)) );
```

So you got the parenthese wrong. You probably meant to write:

```
ratio = sqrt (pow ((maxSpeedRpm/minSpeedRpm), 0.2));
```

The following program line that starts with "ratio" is supposed to =

5√M/mwhere M is maxSpeedRpm and m minSpeedRpm. Please help, I am going cross eyed trying to work this out.

#include <iostream> #include <cmath> using namespace std; int main0() { int maxSpeedRpm, minSpeedRpm; double ratio; cout << "Enter the maximum speed in revolutions per minute"; cin >> maxSpeedRpm; cout << "Enter the minimum speed in revolutions per minute"; cin >> minSpeedRpm; ratio = sqrt((pow(maxSpeedRpm/minSpeedRpm),(1/5))); cout << "The calculated ratio is" << ratio; cin.ignore(); cin.get(); return 0; }

Comments

If you intersperse some blanks you can see for yourself why it doesn't compile:

So you got the parenthese wrong. You probably meant to write:

```
ratio = sqrt( (pow(maxSpeedRpm/minSpeedRpm), (1/5)) );
```

So you got the parenthese wrong. You probably meant to write:

```
ratio = sqrt (pow ((maxSpeedRpm/minSpeedRpm), 0.2));
```

Comments

Yes, white space is your friend - computers don't care, but brains see the structure better.

HINT to the unseasoned or occasional programmer: Pay close attention to at least the first error message generated by the compiler - make sure you know what it means as it will lead you in the direction of your solution. In this case "no matching function for call to 'pow(int)'" was trying to tell you the compiler could not find a function called 'pow' which took one integer parameter (see hemantrautela's Solution 1).

Another trick I like to use to debug complicated math expressions, is to define a series of temporaries and build up the final expression one step at a time. This allows me to see all the intermediary values and it ends up isolating any error messages to exactly and only the offending item, e.g.:

int t1 = maxSpeedRpm/minSpeedRpm; // Here you would see t1 is zero for some data like 5/7, so this needs to be float.

float t2 = pow ( t1, 0.2 ); // And actually pow() needs a double as first argument, but comilers convert it for you.

float t3 = sqrt ( t2 );

A debugger allows you to see each value and understand what's working, what's not.

Mike M.

HINT to the unseasoned or occasional programmer: Pay close attention to at least the first error message generated by the compiler - make sure you know what it means as it will lead you in the direction of your solution. In this case "no matching function for call to 'pow(int)'" was trying to tell you the compiler could not find a function called 'pow' which took one integer parameter (see hemantrautela's Solution 1).

Another trick I like to use to debug complicated math expressions, is to define a series of temporaries and build up the final expression one step at a time. This allows me to see all the intermediary values and it ends up isolating any error messages to exactly and only the offending item, e.g.:

int t1 = maxSpeedRpm/minSpeedRpm; // Here you would see t1 is zero for some data like 5/7, so this needs to be float.

float t2 = pow ( t1, 0.2 ); // And actually pow() needs a double as first argument, but comilers convert it for you.

float t3 = sqrt ( t2 );

A debugger allows you to see each value and understand what's working, what's not.

Mike M.

Very good points, Mike. I hope the original poster will heed your advice!

pow() function having two arguments...as below

c++ , cmath

Thanks

Asp.Net C# Help Blog[^]

c++ , cmath

```
double pow ( double base, double exponent );
long double pow ( long double base, long double exponent );
float pow ( float base, float exponent );
double pow ( double base, int exponent );
long double pow ( long double base, int exponent );
```

Thanks

Asp.Net C# Help Blog[^]

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—SA

Declare all variables you use...

—SA

It's

`b<small><sup>x</sup></small>`

, where b is the base, x is exponent. So, there should be two parameters, not one!See

http://www.cplusplus.com/reference/cmath/pow/

—SA