# How to Input a value, get a result, input that result to calculate another value

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RetiredCheetoXI on 7 Feb 2022
The input is time, which then calculates altitude. This value for altitude is then used to get a value for temperature. How do I make this work? The bolded text is what I just added to it and is not working, everything else works on its own.
prompt = 'Time of flight? (s) ';
t = input(prompt);
tx = t-200:t+200;
if (t <= 45)
h = @(x) 15*x.^2;
fprintf('Altitude: %dm\n\n', h(t))
v = @(x) 30*x;
fprintf('Velocity: %dm/s\n\n', v(t));
if (h <= 11000)
T = (h - 44332.30769230768) / -153.84615384615378;
elseif (h <= 25000)
T = 216.66;
elseif (h <= 47000)
T = (h + 47220) / 333.3;
elseif (h <= 53000)
T = 282.66;
elseif (h <= 79000)
T = (h - 115813) / -222.2;
elseif (h <= 90000)
T = 165.66;
elseif (h <= 110000)
T = (h - 48585) / 250;
end
figure(1)
subplot(2,1,1)
plot(t,h(t),'o',tx,h(tx)), xlabel('Time (s)'), ylabel('Altitude (m)'), title('Altitude vs Time')
subplot(2,1,2)
plot(t,v(t),'o',tx,v(tx)), xlabel('Time (s)'), ylabel('Velocity (m/s)'), title('Velocity vs Time')
elseif (t < 117.5)
h = @(x) 30375 + (1350*x) + 0.5*(-11.5)*x.^2;
fprintf('Altitude: %dm\n\n', h(t))
v = @(x) 1350 - 11.5*x;
fprintf('Velocity: %dm/s\n\n', v(t));
if (h <= 11000)
T = (h - 44332.30769230768) / -153.84615384615378;
elseif (h <= 25000)
T = 216.66;
elseif (h <= 47000)
T = (h + 47220) / 333.3;
elseif (h <= 53000)
T = 282.66;
elseif (h <= 79000)
T = (h - 115813) / -222.2;
elseif (h <= 90000)
T = 165.66;
elseif (h <= 110000)
T = (h - 48585) / 250;
end
figure(2)
subplot(2,1,1)
plot(t,h(t),'o',tx,h(tx)), xlabel('Time (s)'), ylabel('Altitude (m)'), title('Altitude vs Time')
subplot(2,1,2)
plot(t,v(t),'o',tx,v(tx)), xlabel('Time (s)'), ylabel('Velocity (m/s)'), title('Velocity vs Time')
end
Voss on 8 Feb 2022
Replace h with h(t) everywhere in the bolded text.
h is a function. To get h at some given time t, you have to evaluate the function at that time t. That's what h(t) does.

Prahlad Gowtham Katte on 18 Feb 2022
Hello,
As mentioned in the comments please change h to h(t) wherever you are using assignment and comparison operators.
The errors which you got are due to "h" as it is a function handle and it cannot be used in comparison and arithmetic operations but h(t) is a return value of type double which can be used.
Hope it helps.

R2020b

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