Find the exact values of cos(3pi/4 radians) and sin (3pi/4 radians)

solution:

cos(3π/4) = cos(π - π/4)

Since cos(π - π/4) lies in the second quadrant its value will be negative.

cos(π - π/4) = -cos(π/4)

= -1/√2

sin(3π/4) = sin(π - π/4)

= sin(π/4)

sin(3π/4) = 1/√2 = 0.7071

Sin of an angle is +ve in the 2nd quadrant

cos(3π/4 radians) =1/√2 = -0.7071

Find the exact values of cos(3pi/4 radians) and sin (3pi/4 radians)

summary:

The exact values of cos(3pi/4 radians) and sin (3pi/4 radians) are -1/√2 and 1/√2