Respuesta :

elliottou

Answer:

sin(a) = [tex]\frac{7\sqrt{5} }{20}[/tex]

Step-by-step explanation:

cos(2a) = cos²(a)-sin²(a) =  [1-sin²(a)]-sin²(a)= 1 - 2sin²(a)

1 - 2sin²(a)  = -20/29

- 2sin²(a) = -49/40

sin²(a) = 49/80

sin(a) = [tex]\sqrt{\frac{49}{80} }[/tex]

sin(a) = [tex]\frac{\sqrt{49} \sqrt{80} }{80}[/tex] = [tex]\frac{7*4\sqrt{5} }{80}[/tex]

sin(a) = [tex]\frac{7\sqrt{5} }{20}[/tex]

amna04352

Answer:

cos(theta) = 3sqrt(58)/58

sin(theta) = 7sqrt(58)/58

Step-by-step explanation:

Cos(2theta) = 2cos²(theta) - 1

-20/29 = 2cos²(theta) - 1

2cos²(theta) = 9/29

cos²(theta) = 9/58

cos(theta) = sqrt(9/58)

cos(theta) = 3sqrt(58)/58

sin²(theta) = 1 - cos²(theta)

sin²(theta) = 1 - 9/58

sin²(theta) = 49/58

sin(theta) = sqrt(49/58)

sin(theta) = 7sqrt(58)/58

sqrt: square root

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