Example

Title: Trigonometry Identities ( Pythagorean, reciporcal)

Grade: 1300-a Lesson: S3-L3

Explanation: The best way to understand SAT-2 is by looking at some examples. Take turns and read each example for easy understanding.

Examples:

If \$cot⁡(α) = 5/12\$​, where α is in quadrant II, find csc⁡(α).

Step 1a

To find csc⁡(α), we first need to determine the sine of α since \$"csc"⁡(α) = 1/("sin"⁡(α))\$.
Given that \$"cot"⁡(α) = 5/12\$​, and α is in Quadrant II, we can use the Pythagorean identity to find the sine of α.

In Quadrant II:

\$"cot"⁡(α) = "adjacent"/"opposite" = 5/12\$

Explanation: In Quadrant II, apply the Pythagorean theorem to determine sinα, with adjacent side 5 and opposite side 12.

Step 1b

Then use the Pythagorean theorem to find the hypotenuse:

\$"c"^2 = "a"^2 + "b"^2\$

\$"c"^2 = 5^2 + 12^2\$

\$"c" = \sqrt(169)\$

c = 13

So, the hypotenuse c = 13.

Explanation: Utilize Pythagorean theorem for determining the length of the hypotenuse.

Step 1c

Next, find the sine of α using the triangle:

\$"sin"(α) = "opposite"/"hypotenuse" = 12/13\$

Finally, to find csc⁡(α): \$"csc"(α) = 1/("sin"(α))\$

​= \$1 /(12/13)\$

\$= 13/12\$

So, \$"csc"⁡(α) = 13/12\$.​

Explanation: Substitute hypotenuse in sin(α), simplify, then plug sin(α) in csc(α) formula to find csc(α).


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