a-maths~~~~~

這題我曾解答過, 請參閱
http://hk.knowledge.yahoo.com/question/?qid=7007080504865
第三題。
For π/2 < θ < π, sin is +VE, cos is –VE and tan is –VE.
Sum of roots: cos θ + cosec θ = - h / 3
Product of roots: cos θ cosec θ = - 1 / 3
Then,
cot θ = - 1 / 3
tan θ = -3
cos θ = - 1 / √10
cosec θ = √10 / 3
So,
-1 / √10 + √10 / 3 = - h / 3
h = - 7 / √10 = - 7 √10 / 10