If seca+coseca=2thensecpowern+cosecpowern=?

This makes no sense. You must learn correct presentation so people will know what you are saying.

sine - sin(Θ)
sine to any power n - sin^n(Θ)
cosine - cos(Θ)
tangent - tan(Θ)
secant - sec(Θ)
cosecant - csc(Θ)

Trigonometry is based on a picture of a circle with the radius making an angle with the x axis. You carry this picture in your head, not your calculator. Trig is mostly imagination and the rest memorization.

Remember Chief SohCahToa
Sin = Opposite/Hypotenuse
Cosine = Adjacent/Hypotenuse
Tangent = Opposite/Adjacent

Also memorize:
Sec = 1/Cos
Csc = 1/Sin
Cot = 1/Tan