Prove:
sinx/cscx + cosx/secx = 1
cscx = 1/sinx
secx = 1/cosx
therefore:
(sinx/1)/(1/sinx) + (cosx/1)/(1/cosx) = 1
to divide we multiply reciprical
(sinx/1)*(sinx/1) + (cosx/1)*(cosx/1) = 1
sin^2x + cos^2x = 1
that is true therefore we have proved this