Question

lim (4sinx-4)/(lnsinx) as x approaches pi/2?

Answer 1

Are you familiar with derivative?

Answer 2

i'm just quite confused in \[\frac{ \pi }{ 2 }\] because it's the same with 90 right?

Answer 3

yup, pi/2 = 90

Answer 4

i use a calculator to solve sin 90 and sin pi/2, how come the ans is different?

Answer 5

because your calculator can be only one of the mode, either in degree mode or in radian mode.

Answer 6

if u got sin 90 =1 then your calcy is in degree mode

Answer 7

pi/2 RADIANS = 90 DEGREES

Answer 8

What is your question. Is that pi/2 or the imit?

Answer 9

can I have an opinion on what to do?

Answer 10

are u aware of L'Hopital's Rule ?

Answer 11

yep

Answer 12

can u differentiate numerator and denominator ?
and tell me what u get.

Answer 13

*differentiate numerator and denominator separately

Answer 14

\[\frac{ 4cosx }{ \frac{ cosx }{ sinx } }\]

Answer 15

very good :)
that would be 4 sin x , isn't it ?

Answer 16

@lambchamps did u get how it is 4 sin x ??

Answer 17

i got it, thanks for the reminder

Answer 18

ok, so did u get final answer as 0 ?

Answer 19

with \[\frac{ 4cosx }{ \frac{ cosx }{ sinx } }\] cosx would be cancelled right and the sinx would be a numerator so it is now 4sinx, here i got the answer 4

Answer 20

ok, thats correct, i just wanted to confirm that u got 4, thats why i asked whether u got 0.