Solution of an Implicit Function

Hello,

I have an equation which is (200)*(2-0.1*sqrt(x)-2*log(2-0.1*sqrt(x)))-(200)*(2-0.1*sqrt(100)-2*ln(2-0.1*sqrt(100)))=t. I am supposed to find x value for t=1000, but I could not achieve. Can you help me on this?

Thank you

[Torsten]

Use "fzero" to solve your equation for x, given t = 1000.

Answer 1

[Ameer Hamza]

There is no function 'ln' in MATLAB. I guess you meant log to the base e. Try this

f = @(x,t) (200)*(2-0.1*sqrt(x)-2*log(2-0.1*sqrt(x)))-(200)*(2-0.1*sqrt(100)-2*log(2-0.1*sqrt(100))) - t;
f_sol = fsolve(@(x) f(x, 1000), 0);

I suspect that by log you might have meant log to the base 10. In that case replace first log with log10

f = @(x,t) (200)*(2-0.1*sqrt(x)-2*log10(2-0.1*sqrt(x)))-(200)*(2-0.1*sqrt(100)-2*log(2-0.1*sqrt(100))) - t;
f_sol = fsolve(@(x) f(x, 1000), 0);

[Berkay Berk]

Sorry, I meant log as natural logarithm, you're right.

I really stacked and this worked perfectly, thank you.

[Ameer Hamza]

Glad to be of help.