Answer:
\(cos2\theta =\frac{7}{25}\)
Step-by-step explanation:
We have
\(sin\theta =\frac{3}{5}\)
We know
sin²θ + cos²θ = 1
\(\left (\frac{3}{5} \right )^2+cos^2\theta =1\\\\cos^2\theta =\frac{16}{25}\\\\cos\theta =\frac{4}{5}\)
We need to find cos2θ
We have
cos2θ = cos²θ - sin²θ
\(cos2\theta =\left (\frac{4}{5} \right )^2-\left (\frac{3}{5}\right )^2=\frac{7}{25}\)
