document.write( "Question 1176724: If x > 0, \"+%28+arcsin+%28+x%2F2+%29+%2B+arccos+%28+x%2F2+%29+%29+%2F+arctan+%28+x+%29+=+3%2F2+\", solve for x. \n" ); document.write( "
Algebra.Com's Answer #804169 by greenestamps(13200)\"\" \"About 
You can put this solution on YOUR website!


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\n" ); document.write( "Added after seeing the response from tutor @ikleyn....

\n" ); document.write( "She used a nice fact that I overlooked that makes solving this problem relatively easy.

\n" ); document.write( "The numerator is the sum of two angles, each less than pi/2 or 90 degrees, in which the sine of one angle is the cosine of the other. But that makes the two angles complementary, so the numerator of the fraction is just pi/2 (radians), or 90 degrees.

\n" ); document.write( "Then from there the solution is relatively easy.

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\n" ); document.write( "To solve this algebraically, I think you would have to use calculus and the Taylor series expressions for arcsin, arccos, and arctan. And even then solving the problem would probably involve very ugly calculations.

\n" ); document.write( "On the other hand, solving the problem using a graphing calculator is easy -- simply graph the expressions on the two sides of the equation and find where they are equal.

\n" ); document.write( "Note that the domains of arcsin and arctan are from -pi/2 to pi/2 and the domain of arccos is from 0 to pi; so the domain of the expression shown is from 0 to pi/2.

\n" ); document.write( "HOWEVER....

\n" ); document.write( "The topic you have chosen for your post is trigonometry basics -- and solving the problem either of those ways is not basics.

\n" ); document.write( "If solving the problem involves basic trigonometry, then the answer likely lies with one of the \"nice\" acute angles. And for \"nice\" acute angles, with the \"x/2\" as the argument for the sine and cosine and \"x\" as the argument for tangent, x=sqrt(3) seems a likely candidate.

\n" ); document.write( "And, indeed, with the angles in degrees,

\n" ); document.write( "\"arcsin%28sqrt%283%29%2F2%29+=+60\"
\n" ); document.write( "\"arccos%28sqrt%283%29%2F2%29+=+30\"
\n" ); document.write( "\"arctan%28sqrt%283%29%29+=+60\"

\n" ); document.write( "and

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\n" ); document.write( "ANSWER: x = sqrt(3)

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