## danielcb114 Group Title How to factor y^4+1/2+1/(16y^4)? I know that it factors into (y^2+1/(4y^2))^2, but I can't figure out why. I need to simplify this for an arc length integral. Any help is greatly appreciated. 8 months ago 8 months ago

1. danielcb114 Group Title

It is copied correctly; a 3 term sum.

Have you copies it correctly or is Y^4 + (1/2) (y^2) + (1/16)(6^4)?

Does the middle term have the variable y^2 in it?

4. danielcb114 Group Title

Unfortunately, no. I have checked my algebra up to that point and I'm also looking at a solution manual; which skips the factoring step. I haven't seen anything like it before. I'm thinking something similar to completing the square is the way to go, but I'm lost at this point. Thanks for your help, by the way.:)

O.K. I was thinking of a perfect square, but now I see that I was on the wrong track.

6. satellite73 Group Title

there is a typo in your question somewhere for sure

7. satellite73 Group Title

$y^2+\frac{1}{4}y^2=\frac{5}{4}y^2$ once you combine like terms

8. danielcb114 Group Title

Sorry, I just noticed it in the second part. The original question is correct, but the term should be squared.

9. danielcb114 Group Title

I have since corrected it; thank you.

10. satellite73 Group Title

still a typo, since $$(\frac{5}{4}y^2)^2=\frac{25}{16}y^4$$

11. danielcb114 Group Title

Sorry again; I didn't see the missing parentheses. Now it is corrected(knock on wood);)

12. satellite73 Group Title

oooh now i get it $\left(y^2+\frac{1}{4y^2}\right)^2$

13. satellite73 Group Title

happy holidaze! you done?

14. myininaya Group Title

$y^4+\frac{1}{2}+\frac{1}{16y^4}$ $(y^2)^2+2 y^2 \frac{1}{4y^2}+(\frac{1}{4y^2})^2$ This is in the form $a^2+2ab+b^2$ which can be factored into the form: $(a+b)^2$

15. satellite73 Group Title

probably easiest to see if you multiply out and see that it works

16. danielcb114 Group Title

Ahh, yes; I don't know why I didn't see that before. I wanted to express it that way, but for some reason my mind turned off the possibility. Thank you, myininaya, satellite73 and radar. You've made me very happy!

17. satellite73 Group Title

yw (from all of us)

18. myininaya Group Title

I hope you all have a great happy holiday! :)