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.

tan⁻¹ (−20)

Accepted Answer

Hello. Today we're going to be evaluating the following trigonometric expression by using a calculator. So what we are given is tangent inverse of negative 54. Now, before you enter this value into a calculator, you must make sure that the mode is in radiance. Whenever you work with trigonometric expressions, you must have your calculator set to radiance so that you get an accurate value. Now, when you plug in tangent inverse of negative 54 into a calculator, you should get a never ending decimal and the decimal to a couple of digits should be negative 1.552279 and so on. So we're going to need to reduce this value. The question asks us to keep three significant figures of the value of tangent inverse. While three significant figures means we want to keep three nonzero digits of the decimal. The first three non-zero digits are going to be 1.55. So we're going to want to run the decimal to the 100th place. We're going to take a look at the digit to the right of five and that value is two. Since it's less than five, we are not going to change the value of negative 1.55. And what this means is that the value of tangent inverse of negative is going to equal to negative 1.55. And with that being said, the answer to this problem is going to be c 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. tan⁻¹ (−20)

Key Concepts

Inverse Trigonometric Functions

Calculator Functions

Rounding Numbers

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