6/19/25, 10:42 PM cs6515 Exam 1
CS 6515 Exam 1 | Questions and Answers | 2025
Update | 100% Correct – GT.
Correct 63
Incorrect 00
CS 6515 Exam 1
63 Correct terms
Questions and answers
Term
Give this one a go later!
theta = 2pie/n, and omega_n = (1,
plus 1
2pie/n). Multiply them together to
,6/19/25, 10:42 PM cs6515 Exam 1
subsequence you have to use a increase each step
max function
it is the oppose point. 1.) coefficients
(ω_n)^(n/2) == -ω_n 2.) values: A(x_1), A(x_2)... A(x_n)
so
(ω_n)^((n/2)+j == (-ω_n)^j Values are more efficient to do so
Don't know?
2 of 63
Term
why is omega increased in the exponent in order to traverse through
the roots of unity?
Give this one a go later!
theta = 2pie/n, and omega_n = (1, theta = pie/n, and omega_n = (1,
2pie/n). Multiply them together pie/n). Add them together to
to increase each step decrease each step
theta = 3pie/n, and omega_n = (1, theta = 4pie/n, and omega_n = (1,
3pie/n). Divide them to reduce each 4pie/n). Subtract them to adjust each
step step
Don't know?
,6/19/25, 10:42 PM cs6515 Exam 1
3 of 63
Term
what is euler's formula?
Give this one a go later!
cos(theta) + isin(theta) =
tan(theta) = e^(i*theta)
e^(i*theta)
(a,b) = rcos(theta), rsin(theta) sin(theta) - icos(theta) = e^(i*theta)
Don't know?
4 of 63
Term
what is big Oh of longest common substring?
Give this one a go later!
O(n**2) O(mn)
O(n**3) O(nlogn)
, 6/19/25, 10:42 PM cs6515 Exam 1
Don't know?
5 of 63
Term
- What numbers can be used when n = 4 for the roots of unity?
- Can you describe why that is the case?
Give this one a go later!
1,-1,i, -i increasing for sure!!! O(n**2)
- (r,theta)
O(n**3)
- (r, theta) * (1,pie)
Don't know?
6 of 63
Term
What is the direction of roots of unity calculation with FFT vs inverse
FFT?
Give this one a go later!
CS 6515 Exam 1 | Questions and Answers | 2025
Update | 100% Correct – GT.
Correct 63
Incorrect 00
CS 6515 Exam 1
63 Correct terms
Questions and answers
Term
Give this one a go later!
theta = 2pie/n, and omega_n = (1,
plus 1
2pie/n). Multiply them together to
,6/19/25, 10:42 PM cs6515 Exam 1
subsequence you have to use a increase each step
max function
it is the oppose point. 1.) coefficients
(ω_n)^(n/2) == -ω_n 2.) values: A(x_1), A(x_2)... A(x_n)
so
(ω_n)^((n/2)+j == (-ω_n)^j Values are more efficient to do so
Don't know?
2 of 63
Term
why is omega increased in the exponent in order to traverse through
the roots of unity?
Give this one a go later!
theta = 2pie/n, and omega_n = (1, theta = pie/n, and omega_n = (1,
2pie/n). Multiply them together pie/n). Add them together to
to increase each step decrease each step
theta = 3pie/n, and omega_n = (1, theta = 4pie/n, and omega_n = (1,
3pie/n). Divide them to reduce each 4pie/n). Subtract them to adjust each
step step
Don't know?
,6/19/25, 10:42 PM cs6515 Exam 1
3 of 63
Term
what is euler's formula?
Give this one a go later!
cos(theta) + isin(theta) =
tan(theta) = e^(i*theta)
e^(i*theta)
(a,b) = rcos(theta), rsin(theta) sin(theta) - icos(theta) = e^(i*theta)
Don't know?
4 of 63
Term
what is big Oh of longest common substring?
Give this one a go later!
O(n**2) O(mn)
O(n**3) O(nlogn)
, 6/19/25, 10:42 PM cs6515 Exam 1
Don't know?
5 of 63
Term
- What numbers can be used when n = 4 for the roots of unity?
- Can you describe why that is the case?
Give this one a go later!
1,-1,i, -i increasing for sure!!! O(n**2)
- (r,theta)
O(n**3)
- (r, theta) * (1,pie)
Don't know?
6 of 63
Term
What is the direction of roots of unity calculation with FFT vs inverse
FFT?
Give this one a go later!
