Given a temperature, return windchill as a vector.

On a windy day, a temperature of 15 degrees may feel colder, perhaps 7 degrees. The formula below calculates the "wind chill," indicating the temperature that is felt based on the actual temperature (T, in Fahrenheit) and wind speed (W, in miles per hour):

windChill = 35.7 + 0.6T - 35.7W^0.16 + 0.43TW^0.16 In a previous problem you wrote a function to return the wind chill for a single temperature T and wind speed W. In this problem the function is given a single temperature T but a vector of wind speeds WV; your job is to return a vector of wind chills, one for each temperature and wind speed pair. For example, if T is 32 and WV is [1:5], then the function returns the vector [32.9600, 30.3867, 28.7437, 27.5116, 26.5161].

Here is the code given

function windChills = ComputeWindChills(T, WV) windChills = ... ; end

finish the code.

Answer 1

[Image Analyst]

It seems like the question told you the answer, except maybe to put in a few operators like * and . (dot) to fix the syntax.

windChill = 35.7 + 0.6T - 35.7W^0.16 + 0.43TW^0.16

First of all, you'll need to change windChill to windChills to give it the desired name. Then, look up "times, .* - Element-wise multiplication" in the help. You'll also need size() or length() to verify that the size and shape of T and W are the correct and allowable. Inserting 7 characters into the above line of code will produce the correct syntax and correct answer (except for input validation like I mentioned, but you may not need to do that because the problem said you can assume a scalar and a vector are passed in).

[Nirav Patel]

I did

function windChills = ComputeWindChills(T, WV)
windChills = 35.7 + 0.6*T - 35.7*W^0.16 + 0.43*T*W^0.16 ;

however, this assumes it's a scalar. How can I turn this into vector?

[Image Analyst]

You didn't look up "times, .* - Element-wise multiplication" like I suggested. If you had, you would have known to use .^ instead of ^.

function windChills = ComputeWindChills(T, WV, W)
    windChills = 35.7 + 0.6 * T - 35.7 * W .^ 0.16 + 0.43 * T .* W .^ 0.16
end

If T and W are vectors, then windChill will be a vector. But the last term there is (0.43 * T) .* (W.^0.16), not (0.43 * T .* W) .^ 0.16 so make sure you use whichever one you're supposed to.

In your function you don't pass in W, you pass in WV. I don't know what WV is. You don't show it in your formula. What is the use of WV?

Answer 2

[Ousmane Diop]

windChills = 35.7 + 0.6*T - 35.7*W^0.16 + 0.43*T*W^0.16 ;