Question

Given sinX=0.3 , what is cosX ?

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

Answer 1

Answer: The value of cos X = 0.95.

Explanation:

Since we have given that

`\sin X=0.3`

We need to find the value of
`\cos X`

Since we know the relation between sine and cosine.

`\sin^2 X+\cos^2\ X=1\\\\\cos X=√(1-\sin^2\ x)\\\\\cos X=√(1-0.3^2)\\\\\cos X=√(1-0.09)\\\\\cos X=√(0.91)\\\\\cos X=\pm0.953\\\\\cos X\approx \pm0.95`

Hence, the value of cos X = 0.95.

Answer 2

`cos(x)=(+/-)0.95`

Explanation:

we know that

`sin^(2)(x)+cos^(2)(x)=1`

we have

`sin(x)=0.3`

substitute and solve for cos(x)

`0.3^(2)+cos^(2)(x)=1`

`cos^(2)(x)=1-0.3^(2)`

`cos^(2)(x)=0.91`

`cos(x)=(+/-)√(0.91)`

`cos(x)=(+/-)0.95`