Which of the following is a general solution of the equation sin 2x = -rac{1}{2}?
A - HSC - SSCE Mathematics Extension 1 - Question 11 - 2018 - Paper 1
Question 11
Which of the following is a general solution of the equation sin 2x = -rac{1}{2}?
A. x = nrac{ ext{π}}{12} + (-1)^{n}rac{ ext{π}}{2}
B. x = nrac{ ext{π}}{2}... show full transcript
Worked Solution & Example Answer:Which of the following is a general solution of the equation sin 2x = -rac{1}{2}?
A - HSC - SSCE Mathematics Extension 1 - Question 11 - 2018 - Paper 1
Step 1
Determine the general solution for sin 2x = -1/2
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
To solve the equation sin(2x)=−21, we first find the angles which satisfy this condition. The sine function equals -1/2 at certain reference angles in the unit circle. These reference angles can be obtained from the sine function:
The angles are given by:
2x=67π+2nπ
2x=611π+2nπ
Dividing both sides of the equations by 2 gives:
x=127π+nπ
x=1211π+nπ
This can be summarized in a general solution form depending on whether n is even or odd for the possible solutions.
Step 2
Identify the answer choices
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
In the choices provided, we need to determine which of these aligns with our derived general solutions. After evaluating:
A. x=n12π+(−1)n2π is not correct.
B. x=n2π+(−1)n12π is not correct.
C. x=n2π+(−1)n+112π seems plausible.
D. x=n12π+(−1)n2π does not match either.
Therefore, option C is the correct choice as it encapsulates the derived general solutions.