Q. Which of the following is equivalent to sin7π ?sin713πsin78πsin(−7π)sin715π
Properties of Sine Function: Understand the properties of the sine function. The sine function has a period of 2π, which means sin(θ)=sin(θ+2πk) for any integer k. Also, sin(θ)=sin(π−θ) for any angle θ.
Evaluate sin(713π): Evaluate sin(713π).Since 713π=π+76π, we can use the property sin(θ)=sin(θ+2πk) with k=−1 to find an equivalent expression.sin(713π)=sin(713π−2π)=sin(713π−714π)=sin(−7π).This is not equivalent to sin(7π) because sin(θ) is not generally equal to sin(−θ).
Evaluate sin(78π): Evaluate sin(78π).Since 78π=π+7π, we can use the property sin(θ)=sin(π−θ).sin(78π)=sin(π−7π)=sin(76π).This is not equivalent to sin(7π) because 76π is not the same angle as 7π.
Evaluate sin(−7π): Evaluate sin(−7π). Using the odd function property of sine, which is sin(−θ)=−sin(θ), we get: sin(−7π)=−sin(7π). This is not equivalent to sin(7π) because of the negative sign.
Evaluate sin(715π): Evaluate sin(715π).Since 715π=2π+7π, we can use the property sin(θ)=sin(θ+2πk) with k=−1 to find an equivalent expression.sin(715π)=sin(715π−2π)=sin(715π−714π)=sin(7π).This is equivalent to sin(7π) because we have subtracted a full period of the sine function.
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