Thread: Find x, anyone help?

sinx - x multiplied by cosx - (pi/2)=0

please note, working in radians

any method to give the solution thats not an approximation

please email with any solutions

thanks

Originally Posted by LaurenB

sinx - x multiplied by cosx - (pi/2)=0

please note, working in radians

any method to give the solution thats not an approximation

please email with any solutions

thanks

Well the method I propose uses routine algebra and recognition of special angles and values.

Using the null factor law (you might know it by a different name):

.... (1)

or

.... (2)

Regarding equation (1), an obvious exact solution is x = 0. The tricky bit is to show that this actually the only solution ......



Edit: Deleted my remarks on equation (2) for reasons made obvious by an ancient Greek philosopher!

Originally Posted by mr fantastic

.... (2)
Equation (2) is obviously your best chance for exact solutions: and in general where n is any integer.

Do you want to rethink that answer?
Maybe ?

Originally Posted by Plato

Do you want to rethink that answer?
Maybe ?

Thankyou.

And leads to the obvious conclusion .......