<p>Hey I have two questions that I need help on:</p>
<p>1) Given that i = squarerootof -1, (-i)^n-1 = 1 if n =
(A) 2
(B) 3
(C) 4
(D) 5
(E) 6</p>
<p>2) Arccos(sin(arccot(sec 0)))
(A) 0
(B) pi/6
(C) pi/4
(D) pi/3
(E) pi/2</p>
<p>n-1should be multiple of 4 so n=5</p>
<p>pi/4</p>
<p>how'd u get the 2nd one</p>
<p>1) n=5</p>
<p>2) pi/4</p>
<p>once again, how'd u get the second one</p>
<p>i tried to put it in my calc, and didnt get the answer</p>
<p>sec0=1
arcot1=pi/4
cospi/4=sinpi/4</p>