Complete answer

>! 1) c^2=a^2+b^2 pythagoras' theorem.

>! 2) E=mc^2 March the 14th also happens to be Einsteins birthday. The second part refers to C^2 which is the speed of light, frequency refers to speed, radiation wave refers to light and the ^2 is referred to by 'exponential'.

>! 3) maybe (a+b)^2=a^2+b^2+2ab

>! 4) if y=kx^n then dy/dx=nkx^n-1

>! 5) theta=s/r