Question

How does the value of ${\cos ^{ - 1}}\left( { - 0.8090} \right)$ be evaluated by using the calculator?

Answer 1

We have to use the calculator to find the answer to this question. So, find the inverse of $\cos$ function and then put -0.8090 in the brackets. Press enter, it will directly give us the required result.

Complete Step by Step Solution:
According to the question, we have to find the value of ${\cos ^{ - 1}}\left( { - 0.8090} \right)$. It will be difficult to perform it manually. So, we will use the calculator for this. Therefore, first we have to find how to insert the inverse function in the calculator. We will look into it. We can perform the calculation of ${\cos ^{ - 1}}\left( { - 0.8090} \right)$ by using the below mentioned steps –
Step – 1: Find how to insert the inverse function in the calculator, many calculators have a button named inv which means inverse so we can press it and in some calculators, there is the button 2nd so, press it.
Step – 2: Then, find the COS button to specify that we have to find the inverse of $\cos$ function.
Step – 3: Now, we will get the ${\cos ^{ - 1}}$ function inserted in the calculator.
Step – 4: As specified in the question that we have to find the value of ${\cos ^{ - 1}}\left( { - 0.8090} \right)$ , so, we have to put -0.8090 inside the brackets of the ${\cos ^{ - 1}}$ function.
Step – 5: Now, press the enter button or equal the $' = '$ button in the calculator to get the required result. So, the answer we get is $2.513245211$.

Hence, the value of ${\cos ^{ - 1}}\left( { - 0.8090} \right)$ is $2.513245211$.

Note: The above answer given by the calculator is in radians. Many students can make mistakes in this. So, to convert it in the degrees unit simply press the DEG button from the calculator and press the enter button. We will get our required answer in degrees.