1. tanB

Given tan A = 8 and tan (A + B) = -17/6, what is the exact value of tan B?

I got tan B = 13/27 but the textbook tells me the answer is
0.5. How do I get 0.5?

2. Using the formula for tan(a+b) = [tan(a) +tan(b)]\[1-tan(a)tan(b)]

-17/6 = [8 + tan(b)]/[1-8tan(b)]

-17[1-8tan(b)] = 6[8+tan(b)]

-17 +136 tan(b) = 48 + 6tan(b)

130tan(b) = 65

tan(b) =.5

3. To clear...

Originally Posted by Calculus26
Using the formula for tan(a+b) = [tan(a) +tan(b)]\[1-tan(a)tan(b)]

-17/6 = [8 + tan(b)]/[1-8tan(b)]

-17[1-8tan(b)] = 6[8+tan(b)]

-17 +136 tan(b) = 48 + 6tan(b)

130tan(b) = 65

tan(b) =.5
To clear the fractions, you multiplied both side by 6, right?

4. Originally Posted by magentarita
To clear the fractions, you multiplied both side by 6, right?
Hi magentarita,

To clear the fractions, Calculus26 multiplied both sides by 6(1 - 8 tan B).

5. got it

Originally Posted by masters
Hi magentarita,

To clear the fractions, Calculus26 multiplied both sides by 6(1 - 8 tan B).
I understand now. Thanks.