Weekly Reflection 9-14-18

Trigonometric Word Problems:
I will be able to find trigonometric ratios of acute angles.

One example of a trigonometric word problem is:
A 15 foot ladder rests against a tree on level ground and forms a 75 degree angle of elevation. What is the height of the tree? What is the distance of the tree to the base of the ladder.

rotate 90 degrees

The first step in solving this problem would be to go through and find any important information. I know that the ladder leaning against the tree forms a right angle so I will be using a trig ratio. The ladder is 15 feet long and is the hypotenuse so I have one length. The ground under the tree forms a 75 degree angle of elevation. This angle is across from the 90 degree angle. To solve this problem I need to find height and the base of the tree from the ladder. To find height I need to find the Sine (opposite over hypotenuse) 75 degrees = x/15. If I multiply 15 to both sides I can cross out the 15 in the denominator: 15(sin75)=x, x is approximately 14.49 feet. To find the base I need the cos 75=y/15, multiply 15 to both sides to cancel the 15 in the denominator, 15(cos75)=y, y is approximately 3.88 feet. 

One misconception I had was when learning about the inverse of sin I thought that I had to multiply the negative one by sin but really I just had to use the inverse function on the calculator. When Mrs.Burton explained this to the class I could better understand the lesson.

EQ: One mnemonic device that I can use to remember trig ratios is soh-cah-toa (sine:opposite over hypotenuse, cosine: adjacent over hypotenuse, and tangent opposite over adjacent)



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