Ask your own question, for FREE!
Mathematics 6 Online
OpenStudy (anonymous):

PLEASE HELP picture included

OpenStudy (anonymous):

OpenStudy (michele_laino):

I think that the istantaneous rate of change is the first derivative of such functions

OpenStudy (michele_laino):

namely, we have to compare this two functions: \[f'\left( x \right) = \sin \left( {2x} \right),\quad g'\left( x \right) = x\]

OpenStudy (anonymous):

isn't f'(x)= to 2cos(x)sin(x)?

OpenStudy (anonymous):

and g'(x)=1?

OpenStudy (michele_laino):

yes! and \(2 \sin x \cos x= \sin(2x)\)

OpenStudy (anonymous):

i never knew that thanks for that

OpenStudy (michele_laino):

no, please we have this: \[g\left( x \right) = \frac{{{x^2}}}{2} \Rightarrow g'\left( x \right) = x\]

OpenStudy (anonymous):

by using quotient rule

OpenStudy (michele_laino):

namely?

OpenStudy (anonymous):

i dont understand what you mean

OpenStudy (michele_laino):

we have to search for the right \(x\) value, namely we have to search for the value \(x_0\), such that, the subsequent condition holds: \[\sin \left( {2{x_0}} \right) > {x_0}\]

OpenStudy (michele_laino):

of course, we have to refer to the values listed in your exercise

OpenStudy (anonymous):

i see

OpenStudy (michele_laino):

please, if you use a calculator, keep in mind that you have to set the "rad" mode, not "deg" mode

OpenStudy (michele_laino):

"rad" stands for radians

OpenStudy (anonymous):

i put it on rad now

OpenStudy (michele_laino):

ok! Now try, for example the first value: \(x=-0.8\)

OpenStudy (michele_laino):

is \(x=-0.8\) the right value, please?

OpenStudy (anonymous):

do i just plug it into both?

OpenStudy (michele_laino):

yes!

OpenStudy (anonymous):

thats pretty simple actually

OpenStudy (anonymous):

then whichever one lets f(x) have a greater i r o c is the correct one right?

OpenStudy (michele_laino):

you have to compare these quantites: \(\sin(-1.6)\) and \(x_0=-0.8\)

OpenStudy (anonymous):

instantaneous R.O.C.****

OpenStudy (michele_laino):

yes!

OpenStudy (anonymous):

Thank you SO much, you have no idea how much you've helped me today

OpenStudy (michele_laino):

thanks! :) I have solved your exercise. Please what is the right option?

OpenStudy (anonymous):

c) 0.9 and that makes sense because sin cannot be less than -1 and greater than 1

OpenStudy (michele_laino):

correct! since: \(\sin(2 \cdot 0.9)=0.973>0.9\)

OpenStudy (anonymous):

thank you :)

OpenStudy (michele_laino):

:)

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!