Use the abs function to calculate the absolute value.
Please note that you need to include `` to use the `abs` function.

Keyword

【absolute value】

Distance from the origin on the number line. In short, positive values remain unchanged, while negative values are converted to positive values.

The following is how to use the abs function.

abs function

Power = pow(number, exponent);

The following program is an example of calculating absolute value.

Source code

#include <stdio.h>
#include <stdlib.h>

void main(void)
{
    printf("%d\n", abs(10));
    printf("%d\n", abs(-10));

    return;
}

The output of this program is as follows.

Results

10
10

To calculate exponents, use the pow function.
Please note that you need to include `` to use the pow function.

The pow function is used as follows:
Please note that the value will be a double type, so storing it as an integer will result in inaccuracy.

pow function

#include <stdio.h>
#include <stdlib.h>

void main(void)
{
    printf("%d\n", abs(10));
    printf("%d\n", abs(-10));

    return;
}

The following program is an example of calculating exponents.

Source code

#include <math.h>
#include <stdio.h>

void main(void)
{
    printf("%d to the power of %d = %f\n", 5, 2, pow(5, 2));
    printf("%d to the power of %d = %f\n", 8, 3, pow(8, 3));
    printf("%d to the power of %d = %f\n", 2, 10, pow(2, 10));

    return;
}

The output of this program is as follows.

Results

5 squared = 25.000000 8 cubed = 512.000000 2 to the power of 10 = 1024.000000

To calculate a square root, use the sqrt function.
Please note that you need to include `` to use the sqrt function.

Keyword

【square root】

A number that, when squared, becomes that number.
If the original number is the area of a square, the square root corresponds to the length of its side.

The following is how to use the sqrt function.
Please note that the value will be a double type, so storing it as an integer will result in inaccuracy.

sqrt function

square root = sqrt(numerics);

The following program is an example of calculating a square root.

Source code

#include <math.h>
#include <stdio.h>

void main(void)
{
    printf("√%d = %f : %f * %f = %f\n", 100, sqrt(100), sqrt(100), sqrt(100), sqrt(100) * sqrt(100));
    printf("√%d = %f : %f * %f = %f\n", 2, sqrt(2), sqrt(2), sqrt(2), sqrt(2) * sqrt(2));

    return;
}

The output of this program is as follows.

Results

√100 = 10.000000 : 10.000000 * 10.000000 = 100.000000
√2 = 1.414214 : 1.414214 * 1.414214 = 2.000000

It looks like the calculations are accurate because of rounding.
Caution is needed because repeating similar calculations will result in error.

Use the following functions to calculate trigonometric functions.
Note that you need to include <math.h> to use these functions.

Function name	Trigonometric values
sin	sine
cos	cosine
tan	tangent
asin	arc sine
acos	arc cosine
atan	arc tangent

Since all of these functions work in the same way, I will use the tan function as an example from now on.
Here's how to use the tan function.


However, this angle is not the 90 degrees that we typically use as a right angle.
We use a unit of angle called radians.
You can convert from degrees to radians using the following formula.




It's tedious to perform this calculation every time, so I'm creating a macro like this.


The following program calculates the angle of elevation when a person with a height of 160cm looks up at a tree from a distance of 5 meters.
Here's an example of finding the height of the tree when the angle is 40 degrees.


The output of this program is as follows.


Because trigonometric function calculations also produce errors if repeated, caution is needed.