TrigonometryMediumSum, Difference, and Multiple-Angle Formulas ShareSum, Difference, and Multiple-Angle Formulas · Medium problemGiven sinθ=−513\sin\theta=-\tfrac{5}{13}sinθ=−135 with θ\thetaθ in Quadrant III, find cosθ2\cos\dfrac{\theta}{2}cos2θ.A−2626-\dfrac{26}{\sqrt{26}}−2626B−2626-\dfrac{\sqrt{26}}{26}−2626C−5226-\dfrac{\sqrt{52}}{26}−2652D−2627-\dfrac{\sqrt{26}}{27}−2726Check Show answer Walk through it step by step Practice more like this Review this concept