Please find sinX and cosX given that tanX = 3?

Answer 1

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tan(x) = sin(x)/cos(x)= 3

sin(x) = 3cos(x)

sin(x) = 3√[1-sin²(x)]

let y=sin(x)

y = 3√(1-y²)

y² = 9(1-y²)

y² = 9 - 9y²

y² = 9/10

y = ±3/√10

sinX = 3√10/10

cosX = √10/10

or

sinX = -3√10/10

cosX = -√10/10