1.
P = [(-1 + 5k)/(k +1) , (7 + 2k)/(k+1)]
since it lies on 5x-4y=1
[5(-1+5k)/(k+1)] - [4(7+2k)/(k+1)] = 1
(17k-33)/(k+1) = 1
16k - 32 = 0
k = 2
2.
draw the triangle
hyp = 5
opp = 2
adj = √21
cos(270 - θ) = -cos(90 - θ) = -sinθ = -0.4
cot(360 - θ) = -cotθ = √21/2