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Given [tex]\(\sin x = 0.9\)[/tex], what is [tex]\(\cos x\)[/tex]?

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


Sagot :

To solve for [tex]\(\cos(x)\)[/tex] given that [tex]\(\sin(x) = 0.9\)[/tex], we can use the Pythagorean identity in trigonometry, which states:

[tex]\[ \sin^2(x) + \cos^2(x) = 1 \][/tex]

1. We start by substituting the given value of [tex]\(\sin(x)\)[/tex] into the identity. First, calculate [tex]\(\sin^2(x)\)[/tex]:

[tex]\[ \sin(x) = 0.9 \implies \sin^2(x) = (0.9)^2 = 0.81 \][/tex]

2. Next, we substitute [tex]\(\sin^2(x)\)[/tex] into the Pythagorean identity to solve for [tex]\(\cos^2(x)\)[/tex]:

[tex]\[ 0.81 + \cos^2(x) = 1 \][/tex]

[tex]\[ \cos^2(x) = 1 - 0.81 = 0.19 \][/tex]

3. To find [tex]\(\cos(x)\)[/tex], take the square root of [tex]\(\cos^2(x)\)[/tex]:

[tex]\[ \cos(x) = \sqrt{0.19} \][/tex]

4. Calculating the square root gives us:

[tex]\[ \cos(x) \approx 0.4358898943540673 \][/tex]

5. Finally, round this value to the nearest hundredth:

[tex]\[ \cos(x) \approx 0.44 \][/tex]

Thus, the value of [tex]\(\cos(x)\)[/tex] rounded to the nearest hundredth is [tex]\(0.44\)[/tex].