1+1/sin(alpha) =4 the range is for alpha is from 0 to 360 find alpha???

I got the first angle as 19.5, however, the marking scheme stated that there is another angle(160.5) can you please explain how they got the second angle

1 Answer
Nov 17, 2017

See below.

Explanation:

We have:

(sin alpha + 1)/sinalpha = 4

sinalpha + 1 = 4sinalpha

1 = 3sinalpha

sinalpha = 1/3

alpha = 19.5 and ?

We know that sine is positive in the first and second quadrants, thus the reference angle for the second value of alpha is going to be 19.5˚, or alpha_2 = 180˚ - 19.5˚ = 160.5˚.

As required.

Hopefully this helps!