Answer:
- √2/2 which is approximately same as -0.7071
Explanation:
In the 4 quadrants of trigonometry, angle between 0 and 90 degrees have positive sine, cosine and tangent values.
Angles between 90 and 180 degrees have positive sine values while cosine and tangent values are negative.
Angles between 180 and 270 degrees have positive tangent values while sine and cosine values are negative.
Angles between 270 and 360 degrees have positive cosine values while sine and tangent values are negative.
As such,
sin(5π/4) = sin(5×180/4)°
= sin 225°
= - sin(225 - 180)
= - sin 45
= - √2/2 = -0.7071