Posted by **abeer** on Sunday, April 29, 2012 at 9:18pm.

1)Use the definitions sin0(theta) = y/r, cos0(theta) = x/r and/or tan0(theta) = y/x to prove that

cot0(theta) = 1/tan0(theta)

2)For all 0(theta) prove:

a)cos(t) = 1/sec0(theta)

b. sec(t) = 1/cos0(theta)