In Exercises 27–38, use a calculator to find the value of each ex...

Question

In Exercises 27–38, use a calculator to find the value of each expression rounded to two decimal places.
_
cos⁻¹ √5/7

Accepted Answer

Hello, today we're gonna be evaluating the following trigonometric expression. So what we are given is cosine inverse of the square root 3/8. Now, before you enter this value into a calculator, you wanna make sure that the mode of the calculator is in radiance. Whenever you work with trigonometric expressions, you always want to be working in radiance. Now, when you enter cosine inverse of square 3/8 into a calculator, you're going to end up getting a very long, a very long decimal. The decimal that you should get is 1.35, 25618 and so on and so on. So how can we simplify this value while the problem asks us to only keep three significant figures? What this means is the is that we want to keep the first three nonzero digits of the decimal and the first three non-zero digits of the decimal is going to be 1.35. So we're going to need to round this decimal to three digits. We're going to take a look at the digit to the right of five and that is a value of two. So we're going to be keeping 1.35. But we're not gonna be rounding the value up, which means that the value of cosine inverse of square root 3/8 is going to be 1.35. And with that being said, the answer to this problem is going to be D so I hope this video helps you in understanding how to approach this problem. And I'll go ahead and see you all in the next video.

In Exercises 27–38, use a calculator to find the value of each expression rounded to two decimal places. _ cos⁻¹ √5/7

Key Concepts

Inverse Trigonometric Functions

Domain and Range of Cosine

Calculator Functions

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