# Re: need help on this problem

```Garvin (cung@WORLDNET.ATT.NET) wrote:
: do any of you guys/gals know how to do this?
: --------
: Write the following trig expression as an algebraic expression:

:                                                 sin(arcsin x + arccos x)
: --------

: The answer is 1 in case you do it.
: reply as soon as possible.
: thanks
: ____________________________________________________
:   Garvin Cung
:   <cung@worldnet.att.net>
:   http://www.geocities.com/researchtriangle/lab/2240

The solution is quite simple. Just draw a rectangle like depicted below:

-------------
|          /|
|         / |
|        /  |
|       /   |
|      /    |
|    1/     | x
|    /      |
|   /       |
|b /        |
| /         |
|/ a        |
-------------
The length of the diagonal equals 1, and the length of the vertical dimension
equals x. Now angle a equals arcsin(x), and angle b equals arccos(x). There-
fore arcsin(x) + arccos(x) always equals 90 degrees, and sin(90) equals 1.
_______________________________________________________________________________

M. Limpens
E-mail: mpma@wop.wtb.tue.nl
_______________________________________________________________________________

```

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