Final answer:
The value of sin(textangle) is (√21/5).
Step-by-step explanation:
To find the value of sin(textangle), we can use the Pythagorean identity: sin²(textangle) + cos²(textangle) = 1. Since we know that cos(textangle) = -2/5, we can substitute this value into the equation and solve for sin(textangle).
sin²(textangle) + (-2/5)² = 1
sin²(textangle) + 4/25 = 1
sin²(textangle) = 1 - 4/25 = 21/25
sin(textangle) = ±√(21/25) = ±(√21/5)
Since tangent is positive, sin(textangle) must also be positive. Therefore, the value of sin(textangle) is (√21/5)