Can you give me a first step to solve:
cosx = 1 - (2x/π)

Question

Can you give me a first step to solve:
cosx = 1 - (2x/π)

tkhunny · Answer

You have no plan at all?

1) You cannot find a nice, analytic solution.  What are your other options?
2) Are there particular numerical methods at your disposal?

adamaero · Answer

I think it's suppose to be algebraic. Suppose to set it equal to zero? But then what?

tkhunny · Answer

You can think what you want.  It can't be done.  Now, answer my questions.

adamaero · Answer

I don't know how they got pi/2 from them: http://www.slader.com/textbook/9780495011613-stewart-single-variable-calculus-6th-edition/352/exercises/25/

adamaero · Answer

1) only algebraically, cannot use a calculator
2) ?

adamaero · Answer

2) are you talking about double angle formulas or what else?

tkhunny · Answer

IF there is a nice solution, it is only by luck, i.e. the problem statement has been designed to have an unusual answer.

There is NO fancy trick to help you find the solution.  No double angle, no algebraic factoring.  It DOESN'T exist.

You CAN narrow down the solutions.  Off the top of my head, I'd guess the solution is in [0,2].  That certainly narrows down the places to look.