cos θ = sqrt(1 - sin2θ)...tan θ=sin θ/cos θ...sec θ=1/cos θ...csc θ=1/sin θ and cot θ=1/tan θ
For part 2
draw a right triangle with one leg = tan θand the other equal to 1; then the hypotenuse = sqrt(1+tan2θ).
You should be able to get all of the trig functions from that figure!