i dont know how to do these that involve using trig identities to transform one side to the other...

1. (1+ cos [theta]) (1-cos [theta]) = sin^2 [theta].

2. sin [theta]/ cos [theta] + cos [theta]/ sin [theta] =csc [theta] sec [theta]

3. Tan [theta] + Cot [theta]/ tan [theta] = csc^2 [theta]

then there is one i dont get...i can draw the diagram...but the rest i dont get

4. a 6-ft. person walks from the base of a sreetlight directly toward the tip of the shadow cast by the streetlight. when the person is 16 ft from it and 5 ft from the tip of the streetlight shadow, the person's shadow starts to appear beyond the streetlight's shadow.

A) use a trig function to write an equation involving the unknown quantity.

B) what is the height of the streetlight...

i know i am asking for a lot...any help would be great, especially for 4, but any help will be greatly appreciated...thank you