Question

AGAIN HELP ME!!
lim cos (x+1/2 pi)/ x
approaches x-> 0

Answer 1

HI!!

Answer 2

do you get to use l'hopital's rule, or something else?

Answer 3

if you cannot use it, then recognize this as the derivative of
\[\cos(x+\frac{\pi}{2})\] evaluated at \(x=0\)

Answer 4

probably easier to do it the second way in any case
do you know the derivative of cosine?

Answer 5

Actually Im kind of confused ! S: could show me step by step

Answer 6

lets see what you are allowed to use first
do you know derivatives?

Answer 7

i was considering power series ... :)

Answer 8

lol

Answer 9

i have a better idea, lets use a trig identity, then it will take no steps
ok one step

Answer 10

\[\cos(x+\frac{\pi}{2})=-\sin(x)\] so you have
\[-\lim_{x\to 0}\frac{\sin(x)}{x}\]

Answer 11

that limit is supposed to be well known

Answer 12

Oh thanks!!!! I got it :DDDD

Answer 13

did you get \(-1\) ?

Answer 14

\[\color\magenta\heartsuit\]

Answer 15

:D yes