Question

If `sin θ = 3/5`, then cos θ = ?

Options

• `5/3`

• `3/5`

• `4/5`

• `5/4`

Answer 1

`bb(4/5)`

Explanation:

`cos θ = sqrt(1 - sin^2θ)`

∴ `cos θ = sqrt(1 - (3/5)^2)`

∴ `cos θ = sqrt(1 - (9/25))`

∴ `cos θ = sqrt(16/25)`

∴ `cos θ = 4/5`