If cosec teta-cot teta=k than find cosen teta +cot teta

Which triangle congruence postulate or theorem justifies my claim that the steps i made using construction paper and scissors produce an isosceles triangle? was it sss, sas, asa, aas, or hl?

F(x)=x/2-2 and g(x)=2x^2+x-3 find (f+g)(x)

In triangle △abc, ∠abc=90°, bh is an altitude. find the missing lengths. ah=4 and hc=1, find bh.