Use tan to determine angle

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mathmarauder

Junior Member
Joined
Oct 25, 2008
Messages
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Hi All,
Im working on a triangle problem and they ask i find the angles.
I have already found the length of sides, just unsure how to come up with the answer.
in this problem use tan to determine angle A
tan -1(10.6/24.2) roughly = 23.7 degrees
The question is how by using the calculator.
I tried doing 10.6 over 24.2 hitting tan and then hitting -1, but my answer is way off.
How would I get roughly 23.7 degrees?
 
You are getting your answer in radians - you need to convert that number to degrees.

You may want to start the calculations in degree mode.
 
Alrighty...I changed from radians to degrees
ok so I had tan -1 (10.6/24.2)
now i have tan -1 (607.34/1386.56)
from here though...i am still unsure how to make that
roughly equal 23.7 degrees
 
There should be an arctan button on your calculator.

Negative 1 has nothing to do with it. \(\displaystyle tan^{-1}(x)\) means arctangent, not tangent minus 1.

Something like \(\displaystyle tan^{-1}(\frac{10.6}{24.2})=23.65\)

In radians you would get .4128439...

Multiply that by \(\displaystyle \frac{180}{\pi}\) to get the 23.65
 
There is a "tan" button on my calculator; I guess I am just not typing in this in the right order.

And the solution you wrote in looks correct, except for the -1 is not the exponent of tan.
its just tan -1 (10.6/24.2) roughly = 23.65
for example i typed in tan 10.6 divided by 24.2 and the result was nothing close to 23.65
So maybe thisis more of, how to properly use my calculator question.
 
As I said \(\displaystyle tan^{-1}(x)\) means arctangent. It should be on your calculator.

What kind if calculator do you have?. It may have ARCT or ATAN or something like that.
 
Hmm dont have either of those.
only the tan button has the letters tan on it.
Im using windows calculator in scientific mode.
 
mathmarauder said:
Hmm dont have either of those.
only the tan button has the letters tan on it.
Im using windows calculator in scientific mode.
Click to expand...

Read your users manual - find out how you would find "arctan". You may have an "INV" button - you need to learn to use that. Those usage are pretty type of calculator specific - so you need to drag out your "users manual" and study it.
 
Hmm I dont think windows calculator can do that.
I found this calculator online though and it does have a "atan"
button.
I typed this
(atan 10.6/24.2) but i didnt get a result
 
Then check the INV at the top. I believe that's it. Get a real calculator is my advice.
 
Yes, that is it. I just checked. Check the 'Inv' option near the top of the calculator. Then when you hit TAN, it gives the arctangent.
 
Ahh yes I figured it out. Thank you :)
Maybe you could check to see fi I did this right then perhaps,
the question is tan^-1 (2.43)
I got 1.180.
I got it by clicking on the "inv" option, then typing in
2.43 then hitting the "tan" button. Is that answer correct?


Also in the problem cos(sin^-1(-4.81)
i got .9952.
This is how I got that. Once again I clicked the "inv" option
then hit "cos" button then typed in -4.81 then hit the sin button.
Is that answer correct?
Sorry for the trouble and thank you for the help.
 
mathmarauder said:
... the question is tan^-1 (2.43)

I got 1.180

... Is that answer correct? -- Yes, in radians.

Also in the problem cos[sin^-1(-4.81)]

-4.81 is not in the domain of the arcsine function.

In other words, arcsin(-4.81) is not defined within the real number system.
Click to expand...
 
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