need someone to walk me through this question, please:
Use the appropriate rule or combination of rules to find the derivative of the function defined below. \[y=2(\sin(6x)+\cos(x^3))^\frac{ 1 }{ 2 }\]
not even sure how to start this one. ;( looks like it would the the chain rule of course.
first what is derivative of x^{1/2} = ?
1/2x^-1/2
we always go from outer function to inner function
\(y'=2(1/2)(\sin(6x)+\cos(x^3))^\frac{ -1 }{ 2 }d/dx(\sin(6x)+\cos(x^3))\)
options for the right answer are: \[a)2*\frac{ \cos(6x)-\sin(x^3) }{ (\sin(6x)+cox(x^3))^1/2 }\] \[b)\frac{ \cos(6x) +\sin(x^3)}{ (\sin(6x)+\cos(x^3))^\frac{ 1 }{ 2 } }\] \[c)\frac{ 12 }{ 6x^\frac{ 1 }{ 2 } }*\cos(6x)-\frac{ 6 }{ \cos(x^3)^\frac{ 1 }{ 2 } }*\sin(x^3)*x^2\] \[d)\frac{ 1 }{ (\sin(6x)^\frac{ 1 }{ 2 }+\cos(x^3))^\frac{ 1 }{ 2 } }\] \[e)\frac{ 6*\cos(6x)-3x^2*\sin(x^3) }{ (\sin(6x)+\cos(x^3))^\frac{ 1 }{ 2 } }\] f) same as e only 2 outside of the fraction. \[g) \frac{ 2 }{ \sin(6x)+\cos(x^3))^1/2 }\] \[h) \frac{ 6 }{ \sin(6x)^\frac{ 1 }{ 2 } }*\cos6x-\frac{ 3 }{ \cos(x^3)^\frac{ 1 }{ 2 } }*\sin(x^3)*x^2\]
u got my last comment ? how i got that ?
and i had that so far.
yesi got that.
so what is d/dx(sin(6x)+cos(x^3)) ?
do i use the product rule for sin*6x and cos*x^3?
there is no product, so NO u can treat them individually also what is d/dx (sin 6x) = ?
cos6x
-sinx^3
only ?
i mean only cos 6x ?
times 6?
u need chain rule here too, right ?
yes! times 6, because u'll have d/dx(6x)
cox6x*6
cos6x*6
????
yup, what about 2nd term ? d/dx (cos (x^3)) = ?
-sinx^3(3x^2)
absolutely correct! u got it :)
so which option is it ?
e??
put everything together, and u'll get it.
yes, correct :)
awesome!
i hope chain rule is clearer to u now.....
Join our real-time social learning platform and learn together with your friends!