(a) Copy and complete the table of values for the relation \(y = 2 \sin x + 1\)
x
0^\circ
30^\circ
60^\circ
90^\circ
120^\circ
150^\circ
180^\circ
210^\circ
240^\circ
270^\circ
y
1.0
2.7
0.0
-0.7
(b) Using scales of 2 cm to 30^\circ on the x- axis and 2 cm to 1 unit on the y- axis, draw the graph of \(y = 2 \sin x + 1, 0^\circ \leq x \leq 270^\circ\).
(c) Use the graph to find the values of x for which \(\sin x = \frac{1}{4}\).
Verified Correct Answer: .
Step-by-Step Mathematical Solution
(a)
x
0^\circ
30^\circ
60^\circ
90^\circ
120^\circ
150^\circ
180^\circ
210^\circ
240^\circ
270^\circ
y
1.0
2.0
2.7
3.0
2.7
2.0
1.0
0.0
-0.7
-1.0
(b)
(c) \(\sin x = \frac{1}{4}\) (Given)
Multiply through by 2 ; \(2 \sin x = 2 \times \frac{1}{4} = \frac{1}{2}\)
\(2 \sin x = \frac{1}{2} \implies 2 \sin x - \frac{1}{2} = 0\)
Add \(1\frac{1}{2}\) to both sides ;
\(2 \sin x - \frac{1}{2} + 1\frac{1}{2} = 0 + 1\frac{1}{2}\)
\(\implies 2 \sin x + 1 = 1\frac{1}{2}\)
Draw the line \(y = 1\frac{1}{2}\) on the same axis as \(y = 2 \sin x + 1\). The line \(y = 1\frac{1}{2}\) cuts the curve at points P and Q where x = 15^\circ and x = 168^\circ. Hence, the values of x for which \(\sin x = \frac{1}{4}\)are 15^\circ and 168^\circ.
Source: Myschool Past Questions Archive (Record #52606)