MATLAB: USer Defined Function problem

user-defined

Write a user-defined MATLAB function named PBTask4p1_f.m for the following math function with x the input argument and y the output: ?(?) = 3.2? 4 − 5? 2 − 7? The function should work for x being a scalar or a vector.
Use the function to calculate y(-5) and y(4) and display the results in command window b) Use the function to make a plot of the function y(x) for -5 ≤ x ≤ 5. Label the x-axis and y-axis of the plot like the one as follows.
I am new at Matlab ,Any help would be appriciated.Thank you

Best Answer

Since you have already written the function, let me give you some information. In MATLAB '*' is used to indicate matrix multiplication. To do scalar multiplication, change the '*' operator in your code to '.*'. Like this
function w=PBTask4p1(x)
    w = 3.2.*x.^4 - 5.*x.^2 - 7.^x;
end
Then create a vector of x values. Some thing like this
x = -5:0.1:5;
The use this x as input to PBTask4p1 and save the output in a variable. And then you can use plot() function 
plot(x,w)
to create a plot.
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