Weird equation

[Black Integra]

Hi guys.
I was trying to play with trig function and I finally ended up with this equation:

\sqrt{2}sin(\frac{\pi}{2}-d\theta)=1-dx

How can I determine a function \Theta(x) from that equation?

Please, can anyone help me?

[vector22]

1 - dx
is still undefined

[Mark44]

Hi guys.
I was trying to play with trig function and I finally ended up with this equation:

\sqrt{2}sin(\frac{\pi}{2}-d\theta)=1-dx

How can I determine a function \Theta(x) from that equation?

Please, can anyone help me?
Your equation makes no sense. What was the equation you started with?