I need to determine the flight time and name it P2A and I am having a hard time because it is returning as 0

I am using Matlab and this is my code so far.

a=4

b=2

c=7

d=13

syms t

abs(t)

vo=45+a;

do=.044+(b/50)

yo=1

g=9.81

x=(vo*cos(do))*t

y=-(g/2)*t^2+(vo*sin(do))*t+yo

I need to ensure that "t" only takes on postive values and I need to determine the flight time of the baseball using solve and double. Finally I need to call this result P2A

Can you pls help?

Answer 1

[Devesh Bhasin]

Hi Jaden,

For using the 'solve' function, I recommend going through the the examples in the function's documentation. The following is one relevant example that shows the use of 'solve' function to get real solutions:

https://www.mathworks.com/help/symbolic/sym.solve.html#bue1f92-1

For the condition that 't' needs to be positive, the following are the alternatives:

1. You can include the equation 't>0' in your system of equations as an input to the 'solve' function.

2. You can call the assume function before solving the equations as:

assume(t>0)

For more information, please refer to the following documentation for the 'assume' function:

https://www.mathworks.com/help/symbolic/sym.assume.html

3. You can solve for 't^2' instead of 't' and then square the resulting solution at the end. This method is explained in the following MATLAB Answers post:

https://www.mathworks.com/matlabcentral/answers/164468-how-to-make-sure-that-fsolve-gives-only-positive-values-as-the-solution