It's now time to add some trigonometric functions to our program. To make things even more interesting. For this segment, I've chosen three of the most popular functions, sine, cosine, and tangent. Now I should mention that explaining the meaning of sine, cosine and tangent in trigonometry is outside the scope of this course, if you really need to perform these operations in your programs, I assume you already know what they're all about. Otherwise, you wouldn't need them right. However, I have attached two links to this lecture, one of them explaining each of these concepts at a basic level, and the other one containing the trigonometric table of all the values of applying sine, cosine and tangent on a specific angle in terms of either radians or degrees.

By the way, what is the relation between radians and degrees? Well, the formula for converting radians to the degrees is degrees equals radians times 180 divided by pi, and consequently, radians equals degrees times pi divided by 180. our calculator will take the value in degrees provided by the user to calculate each of the three trigonometric functions. Now, let's look at the code for option number eight, which is, of course yet another Elif clause in our code. So firstly, the user is asked to enter a value in degrees, for which to calculate the sign. Next, let's see how the conversion is made. And then how is the result obtained.

So the value integral is provided by the user referenced by the variable value one is first passed to the radians method from within the math module. This method will simply convert the degrees to radians using the formula that I mentioned a couple of minutes ago. Next, we're going To fit the new value to the seen method from within the same module to calculate the sine, and finally, we convert this value to a string and print it out to the screen. Next, looking at the two other options, option nine and 10, corresponding to cosine and tangent, these will work in the exact same way, except one thing, the method used for calculating the final result, the method for cosine is called cos, right here. And the method for calculating the tangent is called tan, which you can see right here. Again, we use degrees as input values for both of these options as well.

And that's it. Of course, finally, we should also handle the case when the user enters an invalid option by mistake using an else clause of course, that simply prints out the invalid option message to the screen and then making use of the continuous statement. simply read the directs the user to the main menu to take another shot. As with any other code thus far in the course, I strongly advise you to add comments to your code. Leave a blank line between code blocks, and also leave a space on the right and left sides of the equal sign when creating a variable. As always be very careful at indentation and do not mix tabs and spaces in your code.

Otherwise, you most likely will end up with errors. Having that said, All that's left to do is to perform a complete test of our application. go through each option and check the results. I'll see you in the next lecture.