Well i'm on a nice track of not understanding anything so here goes another: Given that tan(A+B)=2 and tan A=1.5, use an appropriate formula to find an exact value for tanB.

Thinking to use tan(A+B)=(tanA+tanB)/(1-tanAtanB), plug in and solve for tanB. Is this the correct approach?

Question

Well i'm on a nice track of not understanding anything so here goes another: Given that tan(A+B)=2 and tan A=1.5, use an appropriate formula to find an exact value for tanB. 

Thinking to use tan(A+B)=(tanA+tanB)/(1-tanAtanB), plug in and solve for tanB. Is this the correct approach?

anonymous · Answer

yes

anonymous · Answer

Awesome. 

2=(1.5+tanB)/(1-1.5tanB) 

That's where i get stuck. How does one begin with this? Maybe my brain is just fried from 8 hours...

ganeshie8 · Answer

get rid of fraction first

ganeshie8 · Answer

multiply (1-1.5tanB) thru out

ganeshie8 · Answer

$\large   2 =  \frac{1.5 + \tan B}{1-1.5\tan B}$

multiply (1-1.5tanB) thru out :

$\large   2(1-1.5\tan B) =  1.5 + \tan B$

ganeshie8 · Answer

see if u can finish the rest

ganeshie8 · Answer

u just need to distribute 2 on left hand side,
combine like terms and solve $\tan B$

ganeshie8 · Answer

think of $\tan B$ as  $x$ , maybe..

anonymous · Answer

gooot it. thanks, your a saint.

anonymous · Answer

was the getting rid of the fraction that had me stuck

ganeshie8 · Answer

ahh i see :)