Question

Cos(x)= 40/41 and x lies in Q4. Find sin(x)

Answer 1

sinx =-9/41

Explanation:

cos x= adjacent/hypotenuse = 40/41

sin x = opposite/ hypotenuse = x/41

how do we find o? pythagorean theorem

o²=41² -40²

0= + or - 9

Now is 9 negative or positive?

well since the graph is in quadrant 4, according to CAST Rule, Sin will always be negative

therefore o =-9

sinx = -9/41

Answer 2

Explanation:

`\sin(x) = \sqrt{1 - {cos}^(2)x }`

`\sin(x ) = \sqrt{1 - { ((40)/(41) )}^(2) }`

`\sin(x) = \sqrt{ (1681 - 1600)/(1681) } = \sqrt{ (81)/(1681) }`

sin(x)=±9/41

As x lies in Quadrant 4 , sin(x) = -9/41