Hi,

I have a few questions from this lesson. Hoping you can help clear them up.

Worksheet 134: Problems 1-4 say to write the answers to four places. I thought this means to take it to four places AFTER the decimal point. However,the solution page lists the answers as four numbers total including both before and after the decimal place (ex. 3.022, 30.85). Can you please explain this?

Lesson 134: Inverse functions
The first sentence states that in problem 3 in Lesson 132, you needed to find an angle when you had the 'tan' of the angle. Shouldn't this have said the 'cos' of the angle? The sides given are the 'adjacent' and the hypotenuse, not the 'opposite' and the hypotenuse.

Lesson 134: Inverse functions
The next sentence describes a calculator function using sin-1. However, it tells you to enter .5 first, then press SHIFT SIN-1 =. This is confusing because on our calculator you have to enter SHIFT, SIN-1, then .5 =.

Lesson 134 Solution page:
In Problem 3,the directions from the lesson state you should get the same answer for side a if you keep the angle answer on the calculator and find the sin (or tan)and continue multiplying. However, we got 57.28 (sin 75 x 59.3);and 57.10 (tan 75 x 15.3). I know these two answers are close, but the solution page says both answers should be 57.29. I don't see why our second answer is coming up short since the numbers we're entering are fixed. Can you explain this?

Thanks,
Julia

Dear Julia and Liam,
Thanks so much for sending these comments. I really appreciate it.
Responses are below.
Joan A. Cotter, Ph.D.



The message was posted by Julia (Liam's mom) (from the ip address 67.33.164.148).
Subject:
Geometry Lesson 134
Email:
jdlatlanta@yahoo.com
Message:
Hi, I have a few questions from this lesson. Hoping you can help clear them up. Worksheet 134: Problems 1-4 say to write the answers to four places. I thought this means to take it to four places AFTER the decimal point. However,the solution page lists the answers as four numbers total including both before and after the decimal place (ex. 3.022, 30.85). Can you please explain this?
You are right; it should say "to two decimal places."


Lesson 134: Inverse functions The first sentence states that in problem 3 in Lesson 132, you needed to find an angle when you had the 'tan' of the angle. Shouldn't this have said the 'cos' of the angle? The sides given are the 'adjacent' and the hypotenuse, not the 'opposite' and the hypotenuse.
You are right: it should say cos.


Lesson 134: Inverse functions The next sentence describes a calculator function using sin-1. However, it tells you to enter .5 first, then press SHIFT SIN-1 =. This is confusing because on our calculator you have to enter SHIFT, SIN-1, then .5 =.
You are right. I can't believe I made that mistake.


Lesson 134 Solution page: In Problem 3,the directions from the lesson state you should get the same answer for side a if you keep the angle answer on the calculator and find the sin (or tan)and continue multiplying. However, we got 57.28 (sin 75 x 59.3);and 57.10 (tan 75 x 15.3). I know these two answers are close, but the solution page says both answers should be 57.29. I don't see why our second answer is coming up short since the numbers we're entering are fixed. Can you explain this? Thanks, Julia
The problem is that the angle is not exactly 75. The following procedures will give you 57.29:
Shift cos(15.3/59.3)= 75.04797771 Store this in memory: Shift Sto M
Next: sin RCL M x 59.3= 57.29223333
And: tan RCL M x 15.3= 57.29223333
I will rewrite the directions.

Thanks for clearing up our questions!

Julia & Liam