Respuesta :
Answer:
Part A: Last digit: 8
Step-by-step explanation:
Part A:
To find the last digit of [tex]2^{1999}[/tex], we can observe a pattern in the last digits of powers of 2. The last digit of powers of 2 repeats every 4 powers:
- [tex]2^1 = 2[/tex] ends in 2
- [tex]2^2 = 4[/tex] ends in 4
- [tex]2^3= 8 [/tex] ends in 8
- [tex]2^4= 16[/tex] ends in 6
- [tex]2^5 =32 [/tex] ends in 2
- [tex]2^6 = 64[/tex] ends in 4 (and the cycle repeats)
Since [tex]1999[/tex] is one less than a multiple of 4 ([tex]1999 = 4 \times 499 + 3[/tex]), the last digit of [tex]2^{1999}[/tex] is one position before the end of the cycle, which is 8.
[tex]\dotfill[/tex]
Part B:
Step 1:
State the problem:
Find the last digit of [tex]2^{1999}[/tex].
[tex]\dotfill[/tex]
Step 2:
Describe the strategy:
Recognize the cyclical pattern of the last digits of powers of 2. Since 1999 is one less than a multiple of 4, we know the last digit will be the third one in the cycle.
[tex]\dotfill[/tex]
Step 3:
Details of the solution:
The cycle repeats every 4 powers, so divide the exponent by 4 to find the position in the cycle:
[tex] 1999 = 4 \times 499 + 3 [/tex]
So, the last digit is the third one in the cycle, which is 8.
[tex]\dotfill[/tex]
Step 4:
Explain correctness:
The pattern holds true, and the result aligns with the observation that [tex]2^3[/tex] ends in 8.
[tex]\dotfill[/tex]
Step 5:
Create a new question:
What is the last digit of [tex]3^{2023}[/tex]?