## nickymarden 3 years ago derive the equation.

1. nickymarden

2. Rogue

Senx? What kind of math is this? :o

3. nbouscal

Is that supposed to be sin x?

4. nickymarden

sorry, it's in portugese :) and yes it is.

5. Rogue

Probably. But what is the question asking for? Derive it from...?

6. nbouscal

Okay, so $$g(x)=(\sin x+\sqrt{x})^3\cdot\sqrt{x^4+2}$$ and you're looking for $$g'(x)$$?

7. lgbasallote

no wonder i have seen these sen x for a lot of times i thought they taught secret trigonometry to people -___-

8. nbouscal

So, use the product rule and the chain rule, yeah? Which part are you getting stuck at?

9. nickymarden

i'm sorry for taking long. I was tryig to do it by myself. I just can't do it lol

10. nbouscal

Show us your work so we can see where you're getting lost.

11. nbouscal

First step, product rule, right? So $$f(x)=(\sin x+\sqrt{x})^3, g(x)=\sqrt{x^4+2}$$, and we're finding $$f'(x)g(x)+g'(x)f(x)$$

12. nickymarden

yeeah

13. Rogue

$g(x) = (\sin x + \sqrt x)^3 *\sqrt {x^4 +2}$This gets messy...$\frac {dg}{dx} = (\sin x + \sqrt x)^3 \frac {d}{dx} \left[ \sqrt {x^4 +2} \right] + \sqrt {x^4 +2} \frac {d}{dx} \left[ (\sin x + \sqrt x)^3 \right]$

14. Rogue

As nbouscal said, where do you get stuck?

15. nickymarden

yeah, i get lost in all the algebra.

16. nickymarden

i just erased it all, let me try again lol.

17. nbouscal

Take it one step at a time. First step is to find f'(x), so derive $$(\sin x + \sqrt x)^3$$ using the chain rule.

18. nickymarden

thank you for the help :))