SOLUTION: if tan theta is 1/4 find exact value of tan 2 theta

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Question 1106524: if tan theta is 1/4 find exact value of tan 2 theta
Found 2 solutions by Edwin McCravy, ikleyn:
Answer by Edwin McCravy(20065) About Me  (Show Source):
Answer by ikleyn(52914) About Me  (Show Source):
You can put this solution on YOUR website!
.
tan%282theta%29 = %282%2Atan%28theta%29%29%2F%281-tan%5E2%28theta%29%29


is the standard basic formula for the tangent of the double angle.


Substitute  tan%28alpha%29 = 1%2F4  into this formula:


tan%282theta%29 =  %282%2A%281%2F4%29%29%2F%281-%281%2F4%29%5E2%29 = %28%282%2F4%29%29%2F%281-1%2F16%29 = %28%281%2F2%29%29%2F%2815%2F16%29%29 = 16%2F%282%2A15%29 = 8%2F15.