Math Is Fun Forum

Aartt

Member

Registered: 2010-12-14

Posts: 136

Re: Sin, Cos, and Tan

it did ask for centimeters? well ok sorry about that if i focus too much on one thing i forget another (like i work too much on the problem and i forget the label
)

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Im a 6th grader(ya your all thinking what is he doing here. My answer is I <3 Math and i cannot get enough) I also like Science like Chemistry and Physics(even though i know about nothing about them i still love them because the include the word "MATH" )

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Sin, Cos, and Tan

You did well. Do not worry, but you need to be more thorough. You also need to work in a more orderly fashion. When you answer you need to reply in greater depth.

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Aartt

Member

Registered: 2010-12-14

Posts: 136

Re: Sin, Cos, and Tan

ok

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Im a 6th grader(ya your all thinking what is he doing here. My answer is I <3 Math and i cannot get enough) I also like Science like Chemistry and Physics(even though i know about nothing about them i still love them because the include the word "MATH" )

Bob

Administrator

Registered: 2010-06-20

Posts: 10,180

Re: Sin, Cos, and Tan

hi Aartt,

Yes, be systematic; do each step and tell us what you are getting.

(i)  Check you have got a right angled triangle.  (In our exams it's common to give an isosceles triangle.  The students must cut it down the line of symmetry before they can use trig.)

(ii)  Decide what you know:  angle?  adjacent?  opposite?  hypotenuse?  and what you are asked to calculate.

(iii)  Choose SOH, CAH or TOA as appropriate.

(iv)  Decide the exact form of the formula.

(v)  Substitute numbers and find the required value.

(vi)  Consider, 'is this a sensible value for this problem?'

Here's an example:

See diagram below.

(i) Yes, it has a right angle.
(ii)  I know Adjacent and Hypotenuse and want the angle.
(iii) I'll use CAH
(iv)  So

(v)  so

so x = 36.9

(vi)  8 is not too far under 10 so the angle is probably under 45.  36 seems reasonable.

Please note, I recommended 6 steps and in my example I wrote down all six.

That way, each step is only a little one so it's easier to take; and if you mis-step, we can immediately spot what went wrong and put you straight.

I've got loads of these trig problems and I'm happy to keep posting them if you want to keep trying them.

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

Aartt

Member

Registered: 2010-12-14

Posts: 136

Re: Sin, Cos, and Tan

k thanks bob bundy

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Im a 6th grader(ya your all thinking what is he doing here. My answer is I <3 Math and i cannot get enough) I also like Science like Chemistry and Physics(even though i know about nothing about them i still love them because the include the word "MATH" )

Bob

Administrator

Registered: 2010-06-20

Posts: 10,180

Re: Sin, Cos, and Tan

So do you want another one?

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

Aartt

Member

Registered: 2010-12-14

Posts: 136

Re: Sin, Cos, and Tan

yep

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Im a 6th grader(ya your all thinking what is he doing here. My answer is I <3 Math and i cannot get enough) I also like Science like Chemistry and Physics(even though i know about nothing about them i still love them because the include the word "MATH" )

Aartt

Member

Registered: 2010-12-14

Posts: 136

Re: Sin, Cos, and Tan

soo any time now

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Im a 6th grader(ya your all thinking what is he doing here. My answer is I <3 Math and i cannot get enough) I also like Science like Chemistry and Physics(even though i know about nothing about them i still love them because the include the word "MATH" )

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Sin, Cos, and Tan

Question:

The angle of elevation of the sun is 70 degrees when a tree casts a shadow 14.3 m long. How tall is the tree?

Yes it is tough but you will learn some techniques. Try it.

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Aartt

Member

Registered: 2010-12-14

Posts: 136

Re: Sin, Cos, and Tan

ok so im working with a right triangle so this is the diagram i made Im gonna use Tan because i think i should use tan (just an instinct) so i do O/A = Tan(x) then i replace the varibles with O/14.3 = Tan(70) there now to figure out the varible so first if find the tan of 70 which equals 2.74(i shortened it) then i do 2.74(remeber its shortened i put the full number in)*14.3 and i get 39.29(i rounded it) now to double check i do 39.29(full number not rounded)/14.3 = Tan(x) and i get 2.74 now i feel like just finding the tan so i do tan-¹(2.74) and i get i get 70 yay hope i described it enough SO THE HEIGHT OF THE TREE IS 39.29 M TALL hope i got it right

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Im a 6th grader(ya your all thinking what is he doing here. My answer is I <3 Math and i cannot get enough) I also like Science like Chemistry and Physics(even though i know about nothing about them i still love them because the include the word "MATH" )

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Sin, Cos, and Tan

Hi Aartt;

That is correct. Very good.

Question:

A plane is  at an altitude of 10000 m flying directly toward the coast. The angle from the coastline to the airplane is 30 degrees above the horizontal. How far does the airplane have to go before it flies directly over the coast?

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Aartt

Member

Registered: 2010-12-14

Posts: 136

Re: Sin, Cos, and Tan

D: help plz ive tryed but when i double check it never works could you give me which one i should chose sin cos or tan? plz

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Im a 6th grader(ya your all thinking what is he doing here. My answer is I <3 Math and i cannot get enough) I also like Science like Chemistry and Physics(even though i know about nothing about them i still love them because the include the word "MATH" )

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Sin, Cos, and Tan

Hi Aartt;

Does this help?

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Aartt

Member

Registered: 2010-12-14

Posts: 136

Re: Sin, Cos, and Tan

ok i get the diagram but do i use sin cos or tan sorry but i cant get it right

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Im a 6th grader(ya your all thinking what is he doing here. My answer is I <3 Math and i cannot get enough) I also like Science like Chemistry and Physics(even though i know about nothing about them i still love them because the include the word "MATH" )

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Sin, Cos, and Tan

Hi Aartt;

That is okay. You need to find x. Always run to your sohcahtoa. Yo know the opposite side what is the side marked x called?

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Aartt

Member

Registered: 2010-12-14

Posts: 136

Re: Sin, Cos, and Tan

its adj side so i use tan ?

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Im a 6th grader(ya your all thinking what is he doing here. My answer is I <3 Math and i cannot get enough) I also like Science like Chemistry and Physics(even though i know about nothing about them i still love them because the include the word "MATH" )

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Sin, Cos, and Tan

Hi;

You do not even need to ask me that anymore. You already know!

sohcahtoa...

Tan(angle) = ( side opposite the angle)  / ( side adjacent to the angle )

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Aartt

Member

Registered: 2010-12-14

Posts: 136

Re: Sin, Cos, and Tan

ok so im gonna use tan and the equation is O/A = Tan(x) so replace the vars so 10000/A = Tan(30) so im gonna find the true value of tan(30) which is 0.577(rounded) then i do 10000/0.577 which equals 17320.5 so now im gonna double check my answer so i do 10000/17320 which equals 0.577 and then i click tan-¹ and get 29.99 which is really close to 30 so the distance that the plane has to go is 17320.5 m until it reaches the costline

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Im a 6th grader(ya your all thinking what is he doing here. My answer is I <3 Math and i cannot get enough) I also like Science like Chemistry and Physics(even though i know about nothing about them i still love them because the include the word "MATH" )

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Sin, Cos, and Tan

Soon you will start to know some of the more common angles and the relationships between them.

So you solve:

Flip both of them.

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Aartt

Member

Registered: 2010-12-14

Posts: 136

Re: Sin, Cos, and Tan

huh? i dont get that?

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Im a 6th grader(ya your all thinking what is he doing here. My answer is I <3 Math and i cannot get enough) I also like Science like Chemistry and Physics(even though i know about nothing about them i still love them because the include the word "MATH" )

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Sin, Cos, and Tan

Okay, where is the spot that you are having trouble. What line?

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Aartt

Member

Registered: 2010-12-14

Posts: 136

Re: Sin, Cos, and Tan

i dont get the second line like how the sqrt of 3 = x?

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Im a 6th grader(ya your all thinking what is he doing here. My answer is I <3 Math and i cannot get enough) I also like Science like Chemistry and Physics(even though i know about nothing about them i still love them because the include the word "MATH" )

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Sin, Cos, and Tan

Hi;

That is not what is there. This is what is there.

That is what you got. Not everything is a decimal. I know that is what lots of students are being taught but it just ain't so.

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Aartt

Member

Registered: 2010-12-14

Posts: 136

Re: Sin, Cos, and Tan

ya but what does x equal? oh thats an equivelent fractions *bonks head on desk* ok so x = the sqrt of 30000 right?

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Im a 6th grader(ya your all thinking what is he doing here. My answer is I <3 Math and i cannot get enough) I also like Science like Chemistry and Physics(even though i know about nothing about them i still love them because the include the word "MATH" )

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Sin, Cos, and Tan

Not quite, take a look at what I am doing.

multiply both sides by 10000.

Use your calculator on that.

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.