Given that [tex]$\sin \theta = \frac{15}{17}$[/tex] and [tex]$0 \ \textless \ \theta \ \textless \ \frac{\pi}{2}$[/tex], determine the values of the other trigonometric functions of [tex]$\theta$[/tex].



Answer :

Sure! Let's find [tex]\(\cos \theta\)[/tex] given that [tex]\(\sin \theta = \frac{15}{17}\)[/tex] and [tex]\(0 < \theta < \frac{\pi}{2}\)[/tex].

1. Recall the Pythagorean Identity:
[tex]\[ \sin^2 \theta + \cos^2 \theta = 1 \][/tex]

2. Substitute the given [tex]\(\sin \theta\)[/tex] value:
[tex]\[ \left(\frac{15}{17}\right)^2 + \cos^2 \theta = 1 \][/tex]

3. Square the sine value:
[tex]\[ \left(\frac{15}{17}\right)^2 = \frac{225}{289} \][/tex]

4. Substitute this value into the identity:
[tex]\[ \frac{225}{289} + \cos^2 \theta = 1 \][/tex]

5. Isolate [tex]\(\cos^2 \theta\)[/tex]:
[tex]\[ \cos^2 \theta = 1 - \frac{225}{289} \][/tex]

6. Find a common denominator and subtract:
[tex]\[ 1 = \frac{289}{289} \implies \frac{289}{289} - \frac{225}{289} = \frac{64}{289} \][/tex]
Thus,
[tex]\[ \cos^2 \theta = \frac{64}{289} \][/tex]

7. Take the square root of both sides to solve for [tex]\(\cos \theta\)[/tex]:
[tex]\[ \cos \theta = \sqrt{\frac{64}{289}} = \frac{\sqrt{64}}{\sqrt{289}} = \frac{8}{17} \][/tex]

8. Since [tex]\(0 < \theta < \frac{\pi}{2}\)[/tex], [tex]\(\cos \theta\)[/tex] is positive, making
[tex]\[ \cos \theta = \frac{8}{17} \][/tex]

Given the values of [tex]\(\sin \theta\)[/tex] and [tex]\(\cos \theta\)[/tex], we can also express them in decimal form for completeness:

[tex]\[ \sin \theta \approx 0.8824 \][/tex]

[tex]\[ \cos \theta \approx 0.4706 \][/tex]

Therefore, the values are [tex]\(\sin \theta = \frac{15}{17}\)[/tex] and [tex]\(\cos \theta = \frac{8}{17}\)[/tex], which in decimal form are approximately [tex]\(0.8824\)[/tex] and [tex]\(0.4706\)[/tex], respectively.