looks much better this way:
Solve
cos(x) = - 0.71 on 0 ≤ x < 2π
set your calculator to RAD (radians)
you know that cosx is negative in quads II and III
on mine: "2ndF cos .71 = " to get .78129...
so A = π - .78129... = appr 2.3603
B = π + .78129... = appr 3.9229
Solve
cos
(
x
)
=
−
0.71
on
0
≤
x
<
2
π
There are two solutions, A and B, with A < B
1 answer
1 answer