# Math Is Fun Forum

Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫  π  -¹ ² ³ °

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## #1 Help Me ! » Derivative of arcsec(1/t) » 2013-10-23 13:21:43

infinitebrain
Replies: 1

My textbook keeps saying it is

. Could someone work it step by step and show me how that answer is derived. I would appreciate it because I keep getting lost. Thanks![

## #2 Help Me ! » Sequence question » 2013-03-08 12:55:17

infinitebrain
Replies: 2

Given the sequence

find k
I found the answer as 291, through a tedious guess and check method, but I'd like someone to explain in simpler terms how to find k.

## #3 Re: Help Me ! » Combinatoric/Probability Problem » 2013-03-08 12:34:03

Oh yes thanks guys for this! Thanks to you and a little more studying I figured it out!

## #4 Help Me ! » Combinatoric/Probability Problem » 2013-01-08 16:16:18

infinitebrain
Replies: 25

Hi guys again! I need help with this problem:
Berry Kold Creamery has four flavors of ice cream: vanilla, pistachio,black walnut, and strawberry.The daily sundae has three scoops of ice cream. How many variations of the sundae are there?
I don't need the numerical answer, I would just like how you would set the combination for the question to solve it.
Thanks!
Edited to explain more clearly, I hope this helps bobbym

## #5 Re: Help Me ! » Vector Problem » 2012-12-11 12:43:17

Thank you bob and bobbym! You've both been a enormous help!

## #6 Help Me ! » Vector Problem » 2012-12-10 13:49:32

infinitebrain
Replies: 3

Ima Hyker is camped out in the forest. After breakfast she walks 16 km on a bearing
of 327° then she walks 12 km on a bearing of 237°. What bearing will Ima have to
walk to head straight back to her camp? (nearest degree)

I know how to work it mathematically, but I need a good visual representation ! Could any of you do me a favor and graph it to show me to you can graphically look at this?

## #7 Re: Help Me ! » Probability Question » 2012-11-23 14:35:03

Thank you Agnishom!
Sorry, I went back to look at the documents and it said A is correct, which is 16 2/3%!

## #8 Help Me ! » Probability Question » 2012-11-23 12:25:19

infinitebrain
Replies: 3

Six boys and twelve girls are in a senior class.Half the boys and 25% of the girls wear glasses.What is the chosen probability that a student chosen randomly is a boy,wears glasses,or both? I know the answer is 50%, but could someone could explain to me clearly how you get that answer? Thanks!

## #9 Re: Help Me ! » Need someone to assist me with this question! » 2012-11-11 11:46:44

ohh! I get it Bob! I was confused on how you plug in the second equation, because I kept plugging in 75x - 5. Thank you all for helping me!

## #10 Re: Help Me ! » Need someone to assist me with this question! » 2012-11-11 11:09:37

I keep plugging it in but it keeps saying they met at 48.5 miles, which doesn't connect with any answer choices. So, how am I plugging it in wrong?

## #11 Help Me ! » Need someone to assist me with this question! » 2012-11-11 09:14:12

infinitebrain
Replies: 19

Bob left Colorado City, TX at 5:00 am driving towards Amarillo at an average speed of 68 mph. His sister left 5 minutes later and drove at an average rate of 75 mph. If Amarillo is 232 miles from Colorado City, how far were Bob and his sister from Amarillo when she caught up to him?
a. 178.43 miles
b. 60.71 miles
c. 115.49 miles
d. 53.57 miles
e. 171.29 miles
The only thing I'm really confused about is how do you model that she left 5 minutes later on a calculator?

## #12 Re: Help Me ! » Geometry Problem » 2012-03-04 07:50:16

Ok now bob, just one more question and I promise I'll understand this fully:
how do you use trig the find the angle of the triangle?

## #13 Re: Help Me ! » Geometry Problem » 2012-03-04 07:43:13

oh ok thank you sooo much bob! You've made me see the problem much clearer!

## #14 Re: Help Me ! » Geometry Problem » 2012-03-04 07:27:17

Hi bob bundy, thanks for responding to my post,
on step vii , when you're trying to chop out the green area of the rectangle, why would you need to find the area of the triangle, I'm just wondering how that helps you find out the shaded green area.

## #15 Help Me ! » Geometry Problem » 2012-03-03 16:00:10

infinitebrain
Replies: 15

Hi I'm working on problems for UIL Calculator and I was wondering if anyone could solve this problem: (it's on the picture and it's asking for the shaded area)
And the answer is : .439
It would be great if someone could tell me how this is solved. Thanks.

## #16 Re: Help Me ! » Algebra 2 Math Question » 2012-01-25 15:45:54

Thanks John it helped a bunch! All I was doing was overthinking the situation.

## #17 Re: Help Me ! » Algebra 2 Math Question » 2012-01-25 14:06:26

Ok John I'll try your solution to it. Maybe I'm overthinking this and it's simpler than I imagine.

## #18 Help Me ! » Algebra 2 Math Question » 2012-01-25 13:17:59

infinitebrain
Replies: 3

I really need help on this one part. If someone could help me it would be a BIG help!

Given the 3 x-intercepts (i,-i, and 2)
Write a polynomial equation

I really just need help on how to unfactor the -i back into polynomial form. Thanks.

## #19 Re: Help Me ! » Vertical Math Model » 2011-12-05 16:17:11

ok nevermind bobbym I found it! I worked it out and I think I'm ready Thank you for the assistance though

## #20 Help Me ! » Vertical Math Model » 2011-12-05 13:15:57

infinitebrain
Replies: 3

Does anyone know where I can find questions about them? Or maybe someone else provide a question for me to work?
Specifics:
- Solve for t (time)
- complete the square question
- maximum height (vertex)

I have a test tomorrow and this would greatly help me Thanks!

## #21 Re: Help Me ! » Head-Scatcher (Trigononmetry) » 2011-01-27 10:48:38

Well yours simplies it to just one line. I called mine the "dumbed down" version because I used the sine of 20 degrees to basically work it from there with a series of baby steps.

## #22 Re: Help Me ! » Head-Scatcher (Trigononmetry) » 2011-01-26 14:32:13

very ductible thinking to both of you

## #23 Help Me ! » Head-Scatcher (Trigononmetry) » 2011-01-25 13:16:18

infinitebrain
Replies: 8

Captain Malloy is flying a passenger jet. He is heading east at 720km/hr when he sees an electrical storm straight ahead. He turns the jet 20 degress to the north to avoid the storm and continues in this direction for 1 hr. Then he makes a second turn, back toward his original flight path. Eighty minutes after his second turn, he makes a third turn and is back on course. By avoiding the storm, how much time did Captain Malloy lose from his original flight plan.

## #24 Re: Dark Discussions at Cafe Infinity » Very General » 2010-08-08 05:23:20

It took you 2 years to fully comprehend that bobbbym! Why that's the same amount of time it took me to realize that the moon has another side to it !

but then again he said everybody and I don't know if everybody is "okay" so I'll need to take a survey to see how everyone's doing