How do you use a calculator to evaluate #cos(-110^circ)#?

2 Answers
Mar 1, 2018

See below

Explanation:

To find it using calculator just do the simple steps below:
¤click on cos
¤then type -110
And your calculator will probably show you the answer.

How to calculate it yourself.

#=># #cos (-theta)=cos theta#

#cos (-110°)=cos110°#

#cos (-110°)=-cos70°=-sin20°#

Either simply calculate this by calculator or use a bunch of identities to solve.

Using calculator is a good way but if you are practicing math try making cubic or quartic polynomials also which you can solve using wolframalpha.

Mar 1, 2018

See below...

Explanation:

For this explanation i will be using the regular casio scientific calculator...

First select your "cos" button on the calculator...

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Then input #-110^circ # by pressing "-" then "110" on the keypad

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Now we must close the bracket that has already been opened when we first pressed "cos", press the bracket ")"
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Then press the "ans" button to give the answer, that will be displayed on the display..
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You should get #-0.34202... #

#=> cos(-110^circ) = -0.342 # to 3 decimal places

If you get something different, follow the procedure to get your calc in "degrees" mode

shift #-> # mode #-># 3:Deg