can you help me solve the problems using a simple method

and thanks in advance.

+ Exercises 1. The exponential el can be calculated using the using the following formula: x2 x3 x4 x5 et = 1++ + + 1!2! 3! * 4! 5! The factorial of non-negative integer n is written n! And is defined as follows: n! = n.(n-1).(n - 2).....1 n! = 1 (if n = 0) Write a java program that contains two methods factorial and exp according to the formulas that we mentioned above. The main task for this program is to ask the user to enter a number and calculate its exponential then display the result. > Note that exp method will call factorial method. 2. An integer number is said to be perfect number if the sum of its factors including 1 (but not the number itself) is equal to the number itself. For example 6 is perfect because 6 = 1 + 2 + 3. Write a method is PerfectNumber using the following signature that determines if parameter number is perfect number. Use this method in a main method that determine and prints all the perfect numbers between 1 and 1000. public boolean is PerfectNumber( int number) 3. Write a java method that accepts a binary number and converts it to decimal then display the result. For Example: (110)2 = (610 (22 *1)+(2+ *1) + (20*0) = 6 Additional task: write a method that accepts a decimal and converts it to binary