SOLUTION: Which of the following is a solution to 2sin^2x+sinx-1=0? a. 45 degrees b. 200 degrees c. 240 degrees d. 270 degrees e. 330 degrees

Algebra ->  Logarithm Solvers, Trainers and Word Problems -> SOLUTION: Which of the following is a solution to 2sin^2x+sinx-1=0? a. 45 degrees b. 200 degrees c. 240 degrees d. 270 degrees e. 330 degrees      Log On


   

Question 1170385: Which of the following is a solution to 2sin^2x+sinx-1=0?
a. 45 degrees
b. 200 degrees
c. 240 degrees
d. 270 degrees
e. 330 degrees
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

2sin%5E2%28x%29%2Bsin%28x%29-1=0
2sin%5E2%28x%29-sin%28x%29%2B2sin%28x%29-1=0
%282sin%5E2%28x%29-sin%28x%29%29%2B%282sin%28x%29-1%29=0
sin%28x%29%282sin%28x%29-1%29%2B%282sin%28x%29-1%29=0
%28sin%28x%29%2B1%29%282sin%28x%29-1%29=0
solutions:
if %28sin%28x%29%2B1%29+=0 =>sin%28x%29=-1
if %282sin%28x%29-1%29=0=>sin%28x%29=1%2F2
if sin%28x%29=-1+then sin%5E-1%28-1%29=-90°
if sin%28x%29=1%2F2 then sin%5E-1%281%2F2%29=30°
more solutions:
x=30%2B360n°
x=150%2B360n°
x=270%2B360n°

answer: d. 270 degrees