can some one help me here : if 5 cos x + 3 = 0 and 180 degrees < x < 306 degrees , find the value of 3 tan x + 25 sin^2 x
5cosx + 3 = 0
cosx = -3/5, and 180° < x < 306°
so that x is in quadrant III
did you notice the 3-4-5 right-angled triangle ratios?
so
sinx = -4/5
tanx = 4/3
3tanx + 25sin^2 x
= 3(4/3) + 25(16/25) = 20
( you can use your calculator to check this result
Ø = appr 233.13..)