- #1
Saitama
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- 93
Homework Statement
cos(2tan-1(1/7)) equals-
a)sin(4cot-13)
b)sin(3cot-14)
c)cos(3cot-14)
d)sin(4cot-14)
Homework Equations
The Attempt at a Solution
I am completely stuck in this one. I tried using the formula [itex]2tan^{-1}x=tan^{-1}(\frac{2x}{1-x^2})[/itex]. Using this formula i got [itex]cos(tan^{-1}\frac{7}{24})[/itex].
Now i am stuck, i can't think of anything else on how to proceed.
Any help is appreciated. :)