Question 1042126
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Cot(A) = 4/3 and (A+B) = 90 degree. Find the value of tan(B) = ?
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<pre>
Since A + B = 90°, you have B = 90° - A.

Now, tan(B) = tan(90°-A) = cot(A).

It is a standard trigonometry identity (see, for example, <A HREF=http://www.mathwords.com/t/trig_identities.htm>this site</A>). 

Therefore, tan(B) = cot(A) = {{{4/3}}}.
</pre>

The solution of the other tutor contains very serious error, so disregard it.


In particular, he writes


&nbsp;&nbsp;&nbsp;&nbsp;"If (a+b) = 90 then tan(a+b)= tan 90
&nbsp;&nbsp;&nbsp;&nbsp;We know that tan 90 = 0 then tan(a+b)= 0"


which is totally wrong. Everybody knows that tan(90°) is not defined ("is infinity").


This is why I wrote this post for you.