1_1

#include <iostream>
#include <cmath>

using namespace std;

int factorial(int n) {

    int fact = 1;

    for (int i = 1; i <= n; ++i)
        fact *= i;

    return fact;
}

float calculate(int n, float x) {

    float result = 1;

    for (int i = 1; i <= n; ++i) {

        if (i % 2 != 0)
            result += pow(x, i) / factorial(i);
    }

    return result;
}

void print(int n, float x) {
    cout << "Sum of " << n << " terms at (x = " << x << ") = " << calculate(n, x) << endl;
}

int main() {

    float x;
    int n;

    cout << "Enter x:";

    cin >> x;

    cout << "Enter n:";

    cin >> n;

    print(n, x);

    return 0;
}

3_2.cpp

#include <iostream>
#include <string>

using namespace std;

int* multiply(int arr[], const int length, int num) {
    for (int i = 0; i < length; ++i)
        arr[i] *= num;
    return arr;
}

string toString(int arr[], int length) {

    string str = "[";

    for (int i = 0; i < length; ++i) {

        str += to_string(arr[i]);

        if (i < length - 1)
            str += ", ";
        else
            str += "]";
    }

    return str;
}

int main() {

    const int length = 10;

    int numbers[length] = {
            5,
            15,
            70,
            9,
            88,
            69,
            74,
            87,
            62,
            33
    };

    cout << toString(numbers, length) << endl << toString(multiply(numbers, length, 2), length) << endl;

    return 0;
}

3_3.cpp

#include <iostream>
#include <string>

using namespace std;

int max(const int arr[], int length) {

    if (length <= 0)
        return -1;

    int max = arr[0];

    for (int i = 0; i < length; ++i)
        if (arr[i] > max)
            max = arr[i];

    return max;
}

int min(const int arr[], int length) {

    if (length <= 0)
        return -1;

    int min = arr[0];

    for (int i = 0; i < length; ++i)
        if (arr[i] < min)
            min = arr[i];

    return min;
}

string toString(int arr[], int length) {

    string str = "[";

    for (int i = 0; i < length; ++i) {

        str += to_string(arr[i]);

        if (i < length - 1)
            str += ", ";
        else
            str += "]";
    }

    return str;
}

int main() {

    const int length = 5;

    int numbers[length];

    cout << "Enter the " << length << " numbers:";

    for (int i = 0; i < length; ++i)
        cin >> numbers[i];

    cout << "numbers: " << toString(numbers, length) << endl
         << "max: " << max(numbers, length) << endl
         << "min: " << min(numbers, length) << endl;

    return 0;
}