Use the graph of sin (θ) above to estimate the value of θ when sin (θ) = -0.6 for 0o≤θ≤360o
On the y-axis, each box is 1−05=15 = 0.2unit
On the x-axis, each box is 90−06=906=15o
⇒ θ1=180o+(2.5×15o)=180o+37.5o=217.5o≃218o(2 and half boxes were counted to the right of 180o)
⇒ θ2=270o+(3.5×15o)=270o+52.5o=322.5o≃323o(3 and half boxes were counted to the right of 270o)
∴ θ=218o,323o
