Question

How to sketch the graph of sine from 0 to 360 degrees

Original question: 25 (a) Sketch the graph of y=sinxy=\sin x for 0x3600^\circ \le x \le 360^\circ.

Expert Verified Solution

thumb_up100%(1 rated)

Key concept: The sine graph is one of the easiest full-cycle sketches once you know the anchor points. You do not need a calculator here; the standard angles tell the whole story.

Step by step

To sketch y=sinxy=\sin x for 0x3600^\circ\le x\le 360^\circ, mark the key values of sine at the standard angles:

xxsinx\sin x
00^\circ0
9090^\circ1
180180^\circ0
270270^\circ-1
360360^\circ0

Shape of the curve

  • Start at (0,0)(0,0)
  • Rise smoothly to a maximum at (90,1)(90^\circ,1)
  • Cross the axis at (180,0)(180^\circ,0)
  • Fall to a minimum at (270,1)(270^\circ,-1)
  • Return to (360,0)(360^\circ,0)

The curve should be smooth and wave-like, not piecewise straight. Label the axes clearly, and make sure the peak and trough are at the correct heights.

A neat sketch with these points joined by a smooth sinusoidal curve is the expected graph.

Pitfall alert

Do not plot the sine graph like a zigzag. Another common issue is mixing up sine and cosine: cosine starts at 1, while sine starts at 0. Also remember that the question uses degrees, not radians.

Try different conditions

If the graph were y=sin(x+90)y=\sin(x+90^\circ), it would shift left and match cosine. If the question asked for y=2sinxy=2\sin x, the same x-values would stay the same, but the maximum and minimum would become 2 and -2.

Further reading

amplitude, period, unit circle

FAQ

What are the key points for \(y=\sin x\) from 0° to 360°?

The key points are \((0,0)\), \((90,1)\), \((180,0)\), \((270,-1)\), and \((360,0)\).

Should the sine graph be drawn with straight lines?

No. It should be a smooth wave-like curve passing through the standard sine values.

chat