Question

Which of the following ordered pairs lies on the graph of y = tanx?


(-5pi/2, -1)
(-9pi/4, 1)
(5π, 0)

Answer 1

what is \(\tan(\frac{-5\pi}{2})\)?

Answer 2

@ttop0816 what is \[\frac{\sin(\frac{-5\pi}{2})}{\cos(\frac{-5\pi}{2})}\]

Answer 3

how would i calculate that?! ):

Answer 4

do you know \[\sin(\frac{\pi}{2})\]?

Answer 5

is it 1??

Answer 6

do you know \(\sin(-\frac{\pi}{2})\)?

Answer 7

correct

Answer 8

and sin (-pi/2) would be -1 then?

Answer 9

so what is sin(-5pi/2)?

Answer 10

-1!

Answer 11

correct

Answer 12

what is cos(-5pi/2)

Answer 13

0

Answer 14

oh then for each (-9pi/4, 1) & (5π, 0) i have to do for example
sin (-9pi/4) & cos (-9pi/4) ... more??

Answer 15

so
\(-1\ne\tan(-\frac{5\pi}{2})\)
so (-5pi/2,-1) is not a solution

Answer 16

correct

Answer 17

one of those will work out

Answer 18

well notice we are looking at
\[\tan(x) = \frac{sin(x)}{cos(x)}\]

Answer 19

ohhhhh!!!! then wait

Answer 20

so for -pi/4
we do
\[\frac{sin(-pi/4)}{cos(-pi/4)}\]and see if that equals 1
if it does, then its a solution

Answer 21

i got (-9pi/4, 1)

Answer 22

sin(-9pi/2) = -sqrt(2)/2
cos(-pi/2) = sqrt(2)/2 divide them and you get -1

Answer 23

oh and where did you get -pi/2 from??
also would i use the x cord to calculate sin (-9pi/4) and use the y cord to solve cos (1)?

Answer 24

am i correct with my answer overall?