Question

differentiate with respect to x:
i. y=cos(2x+5)+2xsin3x

ii. y=3x^2-1/x^2+1

Answer 1

have you tried to do it?

Answer 2

yes but i'm not sure its correct

Answer 3

ok can u post your answers coz if theyr wrong ill show you how to do it

Answer 4

i. y^1= -2 sin 2x+5+6x cos 3x

Answer 5

ooh i see lalaly is already on it :P

Answer 6

she's pro

Answer 7

well thats right but u forgot the product rule in the next part

y'= -2sin(2x+5)+6xcos(3x)+2sin(3x)
because 2xsin(3x) is two functions multiplied by eachother so when u want to differentiate that u use the product rule

Answer 8

lol tai thanks xD

Answer 9

im working on the next one

Answer 10

oki im waiting for ur answer:)

Answer 11

\[dy/dx=6x+2x^-3\]

Answer 12

2x^-3?

Answer 13

wait no! lol

Answer 14

\[y=3x^2-1\div x^2+1\]
\[=6x(x^2+1)-2x(3x^2-1)\div(x^2+1)^2\]
\[=6x^3+6x-6x^3+2x \div (x^2+1)^2\]
\[y^1=8x \div (x^2+1)^2\]

Answer 15

goldrush, put brackets please

Answer 16

yup u got it ;) @goldrush18

Answer 17

yeah that's it

Answer 18

omg really

Answer 19

wait checking again

Answer 20

yes its perfect

Answer 21

awesome well i have other questions coming up that i dont understand they are on LIMITS

Answer 22

you should state when you perform dy/dx to show examiner that you know

Answer 23

dy/dx or y^1 thats how we do it as well

Answer 24

it's prime :P not ^1 haha

Answer 25

\[y'\]\[y^{(1)}\]and\[\frac{dy}{dx}\] are all the same tai

Answer 26

i have exams coming up soon so i have to get the hang of these questions

Answer 27

wait it's ^1?

Answer 28

is this your last year btw goldrush?

Answer 29

gold rush im here if u need any help just tag me:)

Answer 30

@Tai yes it is

Answer 31

nice, i have one more year after this

Answer 32

I have soo many exams... lol

Answer 33

thanks @lalaly i do both u and @Tai

Answer 34

SAT1, SSAT Maths2, SSAT physics, SSAT chemistry, AS Maths C1,C2,S1, Macroeconomics, Microeconomics, Physics U1, U2, Practical, Chemistry U1,U2, Practical

Answer 35

15 exams lol

Answer 36

wow thats alot to study for!!

Answer 37

well i have Pure Mathematics, Accounting, Caribbean Studies and Management of Business

Answer 38

:O Caribbean studies? what's that?

Answer 39

for now until i move on to University

Answer 40

are you studying to become a pirate? :P

Answer 41

its basically the whole history about the Caribbean

Answer 42

No lol! its a compulsory subject

Answer 43

and how to become a pirate :]