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Mathematics 6 Online
OpenStudy (amtran_bus):

Derivative help

OpenStudy (amtran_bus):

OpenStudy (amtran_bus):

I know d/dx for it is 1/2 x ^(-1/2)

OpenStudy (amtran_bus):

And 3x^2 for part B.

OpenStudy (freckles):

what do you need help with exactly? pluggin in x=1 into those?

OpenStudy (legomyego180):

multiply down and dubtract one from the exponent. Then rewrite as a fraction.

OpenStudy (amtran_bus):

I guess I'm blind. The step is y'(1)=1/2. Does it mean y=1/2 (1) ^(-1/2)

OpenStudy (freckles):

no y'=1/2(1)^(-1/2)=1/2

OpenStudy (amtran_bus):

But 1/2 ^(-1/2) is not 1/2

OpenStudy (freckles):

why are you calculating 1/2 ^(-1/2)?

OpenStudy (amtran_bus):

I don't understand why we are even plugging x=1 in. We need the derivative for slope. That's easy. But I do not get there the solution manual has a final answer of y'(1)=1/2.

OpenStudy (freckles):

right the slope of the tangnet line at (1,1) can be found by pluggin in the point (x=1,y=1) into the derivative of y=x^(1/2)

OpenStudy (amtran_bus):

I know this is stupid, but will you do it out for me?

OpenStudy (freckles):

\[y'=\frac{1}{2}x^{\frac{-1}{2}} \\ y'|_{(x=1,y=1)}=\frac{1}{2}(1)^{\frac{-1}{2}}=\frac{1}{2}(1)=\frac{1}{2}\]

OpenStudy (freckles):

1 to any power is 1

OpenStudy (freckles):

if the negative exponent then write without negative exponents \[y'=\frac{1}{2 x^{\frac{1}{2}}}\]

OpenStudy (amtran_bus):

Ok. I need to make a note of that. I was multiplying 1/2 *1 first. Need to remember order of operations.

OpenStudy (amtran_bus):

Thank you.

OpenStudy (freckles):

i hate when i leave words out i do that all the time on the internet for some reason if the negative exponent is confusing you*

OpenStudy (freckles):

hey @AmTran_Bus based on the first sentence it sounds like it also wants you to use the graph to estimate the slope

OpenStudy (freckles):

did you also do this?

OpenStudy (freckles):

I would just use the algebraic definition of slope to do this

OpenStudy (amtran_bus):

This is actually for self study...its not an assignment. I'm just reviewing derivatives and working problems.

OpenStudy (freckles):

oh ok

OpenStudy (amtran_bus):

So I'm not really worried bout it. But thanks so much!!!!!!!

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