## bmelyk 3 years ago just wondering how to proceed with this problem.

1. bmelyk

Use the appropriate rule or combination of rules to find the derivative of the function defined below. y=$(16x-4)\sqrt{8x-2}$

2. bmelyk

i know i have to use my product rule, when i do that i get: (16x-4)(1/2)(8x-2)^-1/2 + (8x-2)^1/2 *16

3. hartnn

u forgot chain rule for (8x-2)

4. bmelyk

oh times 8 in there lol. i had that wrote down, lol just forgot to type it.

5. hartnn

then u are correct

6. bmelyk

okay so that i got: $\frac{ 4(16x-4) }{ \sqrt{8x-2} }+16\sqrt{8x-2}$

7. hartnn

absolutely correct!

8. bmelyk

would i take my 4 out of the numerator so i got 16(4x-1) ?

9. hartnn

thats not much of a simplification, but u can !

10. bmelyk

is tehre a way to further simplify this> my answer isn't matching any of the answers on my assingment (this one is a multiple choice)

11. hartnn

what are the options ? u can factor out 16 from both the terms..

12. bmelyk

a) 16- 4/squrt8x-2 B)16(squrt8x-2)+32 times 16x-4/squrt8x-2 c)16-16/squrt8x-2 d)64/squrt8x-2 e)32*2^1/2*x^1/2 -16*2^1/2+(16-4x)/squrt8x-2 f)8*csgn(4x-1)*2^1/2 g)16*squrt8x-2+4(16x-4/squrt8x-2) h)8(16x-4)(squrt8x-2)

13. hartnn

ohh, u can cross-multiply to get the common denominator as $$\sqrt{}8x-2$$

14. bmelyk

so then i have$4(16x-4)+16\sqrt{8x-2}(\sqrt{8x-2})$

15. bmelyk

??

16. hartnn

which is? $$\sqrt{8x-2}\sqrt{8x-2}=8x-2$$

17. bmelyk

i had 320x-16 as my numerator but that's not there as an answer either.

18. bmelyk

19. hartnn

checking, wait..your c option is weird...16-16=0

20. bmelyk

$16-\frac{ 16 }{ \sqrt{8x-2} }$

21. bmelyk

that's what it actually is, it's a little weird when i wrote it the other way lol..

22. bmelyk

so is that right tho?

23. Chlorophyll

My answer's the denom. cancel out! However the way your post the option too complicated to read !!!

24. bmelyk

25. bmelyk

$a) 16-\frac{ 4 }{ \sqrt{8x-2} }$

26. Chlorophyll

= 24 √ ( 8x -1)

27. bmelyk

$b) 16\sqrt{8x-2}+32*\frac{ 16x-4 }{ \sqrt{8x-2} }$

28. bmelyk

$c)16-\frac{ 16 }{ 8x-2 }$

29. bmelyk

$d)\frac{ 64 }{ \sqrt{8x-2} }$

30. bmelyk

$e) 32*2^{\frac{ 1 }{ 2 }}*x^\frac{ 1 }{ 2 }-16*2^\frac{ 1 }{ 2 }+(16x-4)*\frac{ 2^\frac{ 1 }{ 2 } }{ x \frac{ 1 }{ 2 } }$

31. bmelyk

$f)8*csgn(4x-1)*2^\frac{ 1 }{ 2 }$

32. bmelyk

are you sure?

33. bmelyk

$g)16\sqrt{8x-2}+4\frac{ 16-4x }{ \sqrt{8x-2}}$

34. bmelyk

no idea hah.

35. bmelyk

$h)8(16-4x)(\sqrt{8x-2}$

36. hartnn

isn't g) option the same thing what we got ?

37. bmelyk

omg.. look at that.

38. bmelyk

hhaha so it is!!!

39. bmelyk

if you wanna check out my lastest/last question that would be great!

40. Chlorophyll

So it turns out that there's no need to simplified =)

41. bmelyk