Can y'all help me prove the identity tan^2(Y)= 1−cos^2(Y)/cos(Y)

It is saturday morning and jeremy has discovered he has a leak coming from the water heater in his attic. since plumbers charge extra to come out on the weekends, jeremy is planning to use buckets to catch the dripping water. he places a bucket under the drip and steps outside to walk the dog. in half an hour the bucket is 1/5 of the way full. what is the rate at which the water is leaking per hour?

Read the excerpt from gilgamesh: a new english version.gilgamesh backed away. he said,"how dreadful humbaba's face has become! it is changing into a thousand nightmarefaces, more horrible than i can bear.i feel haunted. i am too afraid to go on." §enkidu answered, "why, dear friend,do you speak like a coward? what you just saidis unworthy of you. it grieves my heartwe must not hesitate or retreat."

If three points are collinear, they are also coplanar