SOLUTION: arccos(x)=arccos(x/2) Solve for x, please

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Question 985633: arccos(x)=arccos(x/2)
Solve for x, please
Answer by ikleyn(52799) About Me  (Show Source):
You can put this solution on YOUR website!

Let  alpha = arccos%28x%29  and  beta = arccos%28x%2F2%29.

Then  cos%28alpha%29 = x  and  cos%28beta%29 = x%2F2.

Since  alpha = beta  by the condition,  it implies that

x = x%2F2.

It is possible only if   x = 0.

Answer.  x = 0.