Question 1075749
<pre><font size = 5><b>
<font face="symbol">q</font> = sin<sup>-1</sup>(x)+cos<sup>-1</sup>(x)-tan<sup>-1</sup>(x) for the domain x &#8805; 0,
what is the range?

Because of the inverse sine and cosine functions, 
the domain of <font face="symbol">q</font> is 0 &#8804; x &#8804; 1, 

We find the derivative of <font face="symbol">q</font>

{{{d(theta)/dx}}}{{{""=""}}}{{{1/sqrt(1-x^2)-1/sqrt(1-x^2)-1/(1+x^2)}}}

The first two terms cancel and we have

{{{d(theta)/dx}}}{{{""=""}}}{{{-1/(1+x^2)}}}

Since the derivative of <font face="symbol">q</font> is negative, the function <font face="symbol">q</font>
decreases everywhere on the open part of its domain,
which is 0 < x < 1.
[<font face="symbol">q</font> is not differentiable at the endpoints 0 and 1, although 
<font face="symbol">q</font> is defined at those endpoints]

We evaluate <font face="symbol">q</font> at the endpoints of the 
domain of <font face="symbol">q</font> : 

Substitute x = 0

<font face="symbol">q</font> = sin<sup>-1</sup>(0) + cos<sup>-1</sup>(0) - tan<sup>-1</sup>(0) = 0° + 90° - 0° = 90°

Substitute x = 1

<font face="symbol">q</font> = sin<sup>-1</sup>(1) + cos<sup>-1</sup>(1) - tan<sup>-1</sup>(1) = 90° + 0° - 45° = 45°

Thus the range for <font face="symbol">q</font> for the domain
 
0 &#8804; x &#8804; 1

is

45° &#8804; <font face="symbol">q</font> &#8804; 90°

Edwin</pre></font></b>