SOLUTION: Given that tan A=1/5. Find the values of tan 2A, tan 4A and tan (45�-4A). I have calculated the value of tan 2A by using tan 2A = 2tan A/1-tan^2A and the answer I have got is 5/12

Question 1117096: Given that tan A=1/5. Find the values of tan 2A, tan 4A and tan (45�-4A).
I have calculated the value of tan 2A by using tan 2A = 2tan A/1-tan^2A and the answer I have got is 5/12. Now I don't know how to solve further. Please give me a idea for it.
Answer by ikleyn(52835) (Show Source): You can put this solution on YOUR website!
.

1.  tan(2A) =  =  =  =  =  = .


    So, your calculations for tan(2A) are correct.




2.  To calculate  tan(4A),  notice that  4A = 2*(2A);  thus  tan(4A) = tan(2*(2A)).


    So, you can repeat THE SAME PROCEDURE  to get  tan(4A)  starting from  tan(2A), which you just know.




3.  tan(45�-4A) =  = .


    So, when you will find  tan(4A)  (as I described in n.2), you will be in position to find  tan(45�-4A).

RELATED QUESTIONS
If tan a=1/5 and tan b=1/239, find the value of... (answered by espeigel)

Find the exact values of sin 2a, cos 2a, and tan 2a. tan a=2, pi < a <... (answered by lwsshak3)

find the exact values of sin 2a, cos 2a, and tan 2a when tan a = 2, π < a <... (answered by lwsshak3)

Find the value of tan(Tan^-1... (answered by fractalier)

If tan A = 4/3, and B =45�, find the value of... (answered by ikleyn)

Compute the exact value of tan{tan^-1{1/5}+... (answered by stanbon)

Find the exact value of each trig expression Tan 135 - tan 15 ---------------------- 1 (answered by stanbon)

If {{{tan(3x) tan (2x) = tan (pi/4)}}}, find the value of {{{sin(5x)}}}, given that {{{0... (answered by ikleyn)

please help me solve this question: Given that tan (x+y)=3 and tan (x-y)=1, find the... (answered by lwsshak3)