Question

Given sinx=0.5 , what is cosx ?

Enter your answer as a decimal in the box. Round only your final answer to the nearest hundredth.

Answer 1

The arc sine of 0.5 is 30 degrees Therefore x = 30 degrees
The cosine of x = cosine of 30 degrees = 0.86603
(rounded to nearest hundredth is .87)

Answer 2

The value of cosx is
`\pm0.87`

Explanation:

We have been given that
`\sin x= 0.5`

We know the relation between sine and cosine

`\sin^2x+\cos^2x=1`

On solving the equation for cosx, we get

`\cos x=\pm√(1-\sin^2x)`

Plugging the value of sinx, we get

`\cos x=\pm√(1-(0.5)^2)`

On simplifying, we get

`\cos x=\pm√(0.75)\\\\\cos x=\pm0.87`

Therefore, the value of cosx is
`\pm0.87`