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sin(arcsin x + arccos x)

 Feb 9, 2017

Best Answer 

 #4
avatar+118654 
+5

Hi asinus,

Your answer does not make sense.

x is not an angle it is a ratio. so you cannot have sin(x)

 

Certainly if the angles are both 45 degrees this will work

 but one angle might be 30 degrees and the other 60degrees

or  as I have said, one is x degrees and the other is 90-x degrees.

Think of this triangle and it might help you understand.  :)

 

 Feb 9, 2017
 #1
avatar+14985 
+5

sin(arcsin x + arccos x)

 

\(sin(arcsin\ x+arccos\ x)\)  

 

If

 

\(sinx=cosx\) 

 

then

 

\(sinx=cosx=\frac{\sqrt 2}{2}\)

 

\(\large sin(arcsin\frac{\sqrt 2}{2}+arccos\frac{\sqrt 2}{2})=sin(\frac{\pi}{4}+\frac{\pi}{4})=sin\frac{\pi}{2}=1\)

 

 

 

laugh  !

 Feb 9, 2017
edited by asinus  Feb 9, 2017
 #4
avatar+118654 
+5
Best Answer

Hi asinus,

Your answer does not make sense.

x is not an angle it is a ratio. so you cannot have sin(x)

 

Certainly if the angles are both 45 degrees this will work

 but one angle might be 30 degrees and the other 60degrees

or  as I have said, one is x degrees and the other is 90-x degrees.

Think of this triangle and it might help you understand.  :)

 

Melody  Feb 9, 2017
 #2
avatar+118654 
+10

sin(arcsin x + arccos x)

 

\(sin(arcsin x + arccos x)\\ let\;\;asin(x)=\theta\\ then\;\;acos(x)=90-\theta\\ so\\ sin(arcsin x + arccos x)=sin(\theta+90-\theta)=sin(90)=1\)

 Feb 9, 2017
 #3
avatar+129840 
0

Thanks, Melody.....I couldn't think how to do this one....but ....I see what you did there....!!!!

 

 

cool cool cool

 Feb 9, 2017
 #5
avatar+118654 
0

Thanks Chris, I had to think about it a little bit too :)

Melody  Feb 9, 2017
 #6
avatar+129840 
0

Yeah........I still have to wrap my brain around it.....LOL!!!!

 

 

cool cool cool

 Feb 9, 2017

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