# Multiple Choice Answers? (1 Viewer)

#### tommo727

##### Member
What did everyone do for multi choice?

#### InteGrand

##### Well-Known Member
Here's what I got based on skimming through them:

$\bg_white \noindent 1 (C); 2 (C); 3 (A); 4 (D); 5 (B); 6 (C); 7 (D); 8 (C); 9 (A); 10 (B)$

#### samcalamos

##### New Member
Isn't 5: A since a rotation by -i is a rotation pi/4 clockwise?

#### tommo727

##### Member
Can you explain 7? And I thought 2 was A. Agree with the rest

#### InteGrand

##### Well-Known Member
Isn't 5: A since a rotation by -i is a rotation pi/4 clockwise?
Well -i is cis(-pi/2), so it rotates by pi/2 clockwise.

#### JAMLO

##### Member
Isn't 5: A since a rotation by -i is a rotation pi/4 clockwise?
No B is correct because if you rationalise the complex number given you get -i which is a rotation of 90 degrees towards the right, hence clockwise. Hence B is correct

#### samcalamos

##### New Member
Feels when you thought pi/4 was 90 degrees hahaha oh god...

#### InteGrand

##### Well-Known Member
Can you explain 7? And I thought 2 was A. Agree with the rest
For Question 2, option (A) doesn't satisfy p'(1) = 0. Remember, to be a multiple root, we also need p'(1) = 0.

For Question 7, it's based on the following result (should be in at least one of the textbooks, maybe Arnold and Arnold?):

$\bg_white \noindent The graphs of xy = \frac{k}{2} and x^2 -y^2 = k are the same but with different axes; they are 45^\circ rotations of each other, and the asymptotes of one are the axes of the other. So we need \frac{k}{2} = 8, so k=16.$

#### tommo727

##### Member
Correct me if I'm wrong but I am pretty sure for A P'(1) = 0 and for C P'(1) = 1

#### InteGrand

##### Well-Known Member
Correct me if I'm wrong but I am pretty sure for A P'(1) = 0 and for C P'(1) = 1
Remember, the constant terms disappear when we differentiate.

#### tommo727

##### Member
God damn it you're right. Another -1