Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: Trigonometry
Replies: 4   Last Post: Dec 8, 2004 1:04 AM

 Messages: [ Previous | Next ]
 Aaron Eilers Posts: 12 Registered: 12/6/04
Re: Trigonometry
Posted: Dec 3, 2004 3:20 AM

"Jason" &lt;jasonpush@hotmail.com&gt; wrote in message
<a href="news://es5vq0p1hld42fjm5o319h0b32vcd9kf2o@4ax.com...">news://es5vq0p1hld42fjm5o319h0b32vcd9kf2o@4ax.com...</a>
&gt; If sin x = 1/3 and pi/2 &lt; X &lt; 2pi
&gt; Find:
&gt;
&gt; (i) tan x
&gt;
&gt; (ii) cos x
&gt;
&gt; therefore x is in the 3rd quadrant as sin x = 1/3 = O/H (+)
&gt;
&gt; so as per pythag if a^2 = b^2 + c^2 then c^2 = a^2 - b^2 =
&gt;
&gt; 3^2 - 1^2 = 8 so sqrt of 8 approx= 2.83, so tan = O/A = 1/2.83 and
&gt;
&gt; cos = A/H = 2.83/3
&gt;
&gt;
&gt; is this correct?
&gt;
&gt; Thank you
&gt;
&gt; Jason

Looks good to me, except if you are going to approximate the square root of
8, why not estimate tan x as 0.35 and cos x as .94. Otherwise, write them in
terms of the square root of x, tan x = sqrt(8)/8 and cos x = sqrt(8)/3.

Aaron

--
submissions: post to k12.ed.math or e-mail to k12math@k12groups.org
private e-mail to the k12.ed.math moderator: kem-moderator@k12groups.org
newsgroup website: <a href="http://www.thinkspot.net/k12math/">http://www.thinkspot.net/k12math/</a>
newsgroup charter: <a href="http://www.thinkspot.net/k12math/charter.html">http://www.thinkspot.net/k12math/charter.html</a>

Date Subject Author
12/3/04 Aaron Eilers
12/3/04 Guess who
12/3/04 George Cox
12/8/04 Nat Silver