Cos(2θ) = cos²θ - sin²θ = (1-sin²θ)-sin²θ = 1-2(7/9)^2 = -17/81
Answer:
Second time here for the points
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Answer:
copy and paste
Explanation:
https://www.khanacademy.org/math/algebra2/x2ec2f6f830c9fb89:eq/x2ec2f6f830c9fb89:extraneous-sol/v/finding-radical-equation-with-given-extraneous-solution
X-6y=19
-x+2y=-31
________
0-4y= -12
-4y=-12
y= -12/-4
y=3