Pre-Calc Exam Notes 12

Pre-Calc Exam Notes 12 - 12 Chapter 1 • Right Triangle...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 12 Chapter 1 • Right Triangle Trigonometry §1.2 Example 1.10 radicallow 3 3 ◦ A B C D E F radicalBig 3 2 radicalBig 3 2 2 1 45 ◦ Find the sine, cosine, and tangent of 75 ◦ . Solution: Since 75 ◦ = 45 ◦ + 30 ◦ , place a 30 − 60 − 90 right triangle △ ADB with legs of length radicallow 3 and 1 on top of the hypotenuse of a 45 − 45 − 90 right triangle △ ABC whose hypotenuse has length radicallow 3, as in the figure on the right. From Figure 1.2.2(a) we know that the length of each leg of △ ABC is the length of the hypotenuse divided by radicallow 2. So AC = BC = radicallow 3 radicallow 2 = radicalBig 3 2 . Draw DE perpendicular to AC , so that △ ADE is a right triangle. Since ∠ BAC = 45 ◦ and ∠ DAB = 30 ◦ , we see that ∠ DAE = 75 ◦ since it is the sum of those two angles. Thus, we need to find the sine, cosine, and tangent of ∠ DAE . Notice that ∠ ADE = 15 ◦ , since it is the complement of ∠ DAE ....
View Full Document

This note was uploaded on 01/21/2012 for the course MAC 1130 taught by Professor Dr.cheun during the Fall '11 term at FSU.

Ask a homework question - tutors are online