Answer:
![(√(26))/(26)](https://img.qammunity.org/2021/formulas/mathematics/high-school/zwtpqws04sqm1o3jzpxj1s6edun7wrnp4o.png)
This is the square root of 26 over 26. The second 26 is not inside the square root. You can type it in as sqrt(26)/26.
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is in Q1 so
![\sin(\theta) > 0](https://img.qammunity.org/2021/formulas/mathematics/high-school/bfy8h327f6qrlmki966fp9gxpb736b1c1y.png)
Use the trig identity below and plug in the given value to get...
![\sin\left((x)/(2)\right) = \pm \sqrt{(1-\cos(x))/(2)}\\\\\sin\left((2\theta)/(2)\right) = \pm \sqrt{(1-\cos(2\theta))/(2)}\\\\\sin(\theta) = \sqrt{(1-\cos(2\theta))/(2)} \ \ \text{since } \ \sin(\theta) > 0\\\\\sin(\theta) = \sqrt{(1-(12)/(13))/(2)}\\\\](https://img.qammunity.org/2021/formulas/mathematics/high-school/1ac5nucllid3w7zk0nhdc1nvvfhnfvd678.png)
![\sin(\theta) = \sqrt{(1)/(26)}\\\\\sin(\theta) = (√(1))/(√(26))\\\\\sin(\theta) = (1)/(√(26))\\\\\sin(\theta) = (1*√(26))/(√(26)*√(26)) \ \ \text{ rationalizing denominator}\\\\\sin(\theta) = (√(26))/(26)\\\\](https://img.qammunity.org/2021/formulas/mathematics/high-school/rjocchfcdbh2ife5lws4w6qbrig9zfg0cl.png)
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Edit:
To find cos(theta), we use the pythagorean identity below
![\sin^2(\theta) + \cos^2(\theta) = 1\\\\\cos^2(\theta) = 1-\sin^2(\theta)\\\\\cos(\theta) = √(1-\sin^2(\theta))\ \ \text{cosine is positive in Q1}\\\\\cos(\theta) = \sqrt{1-\left((1)/(√(26))\right)^2}\\\\\cos(\theta) = \sqrt{1-(1)/(26)}\\\\\cos(\theta) = \sqrt{(25)/(26)}\\\\\cos(\theta) = (√(25))/(√(26))\\\\\cos(\theta) = (5)/(√(26))\\\\\cos(\theta) = (5√(26))/(√(26)*√(26))\\\\\cos(\theta) = (5√(26))/(26)\\\\](https://img.qammunity.org/2021/formulas/mathematics/high-school/mbmz2gfwqjwkishdj9ud6addk2xg6hvn1s.png)