Question

here is a graph and the question , the equation of the first dervative is ?

Answer 1

do you know what the derivative of cos is?

Answer 2

no sorry that is what the question is

Answer 3

http://tutorial.math.lamar.edu/cheat_table.aspx there is a cheat sheet here that you might benefit from.

Answer 4

you're supposed to prove first derivative of cosx equals something ?

Answer 5

or u just want to write out the answer ?

Answer 6

yea

Answer 7

yea for what ?

Answer 8

lol? proof or answer. and i dont think the answer to such a question can just be given.

Answer 9

its to simple if its just given

Answer 10

i have never seen this type of question in my life

Answer 11

are you taking calculus?

Answer 12

yea

Answer 13

have you proved any derivatives with the limit definition yet?

Answer 14

yea

Answer 15

i am actually profeesinal at that

Answer 16

so. take the limit as x-->0 of cosx by
cos(x+deltax)-cosx/deltax

Answer 17

what do u mean by delta?

Answer 18

the change in. call it h if you want, some books do

Answer 19

can u help me solve that ?? i dont get it

Answer 20

do you know your sum identity for trig functions? that is your first step

Answer 21

ummm

Answer 22

cos(A+B)=cosAcosB-sinAsinB

Answer 23

could u actually make the equation in a better form i dont understand u u quite mean

Answer 24

\[\lim_{x \rightarrow 0}\frac{ \cos(x+\Delta x)-\cos }{ \Delta x }\]

Answer 25

sin is easier if you want to do it.

Answer 26

should be delta x approaches 0, but i dont think that is stopping you at this point.

Answer 27

i am getting -5sinx+2 is it correct?

Answer 28

no. show me your work

Answer 29

there is soo much

Answer 30

i know, just drop all notation and give me the computations using the equation editor

Answer 31

-5sinx, i think now its right

Answer 32

i only have 5 steps and thats because im thorough and that is wrong. but close.

Answer 33

and in one step you have to remember the squeeze theorem limits with sin. and there are 2 ways to factor out the cos side and one you have to use the squeeze theorem limit and the other is more simple.. if that hint helps.

Answer 34

5cosx , i did agian right

Answer 35

that is incorrect.

Answer 36

let me show you the first step

Answer 37

\[\frac{ \cos x \cos \Delta x-\sin x \sin \Delta x-\cos x }{ \Delta x }\]

Answer 38

now group your sins and cos's and separate into 2 fractions

Answer 39

im off to bed but i will give you the next step first.
\[\frac{ \cos x \cos \Delta x-\cos x }{ \Delta x }-\frac{ \sin x \sin \Delta x }{ \Delta x }\]

Answer 40

i did hat i get 5cosx +2 right ?

Answer 41

no that is incorrect