Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.
Trending News
Can you help me with this trig. problem?
If cosx = 7/25 and tan x < 0, find:
Tan (Theta/2)
1 Answer
- ☮ VašekLv 51 decade agoFavorite Answer
Look at my other today's answer on your question to find
|sin(x/2)| = sqrt((1-cos x)/2)
Similarly, it holds
|cos(x/2)| = sqrt((1+cos x)/2)
and thus
|tan(x/2)| = sqrt((1-cos x)/(1+cos x)).
Here, we have |tan(x/2)| = sqrt((1-(7/25)) / (1+(7/25))) = sqrt((18/25) / (32/25)) = sqrt(18/32) = sqrt(9/16) = 3/4.
The reasoning for the sign is exactly the same as in the question I referred to with the same result: negative.
The answer: tan(x/2) = -3/4.
