Bhawna L said:
The function is ##C(t)=\frac{30⋅t}{200000+t}##
OK, got it. Mind your parentheses, that's not the function you originally typed.
If you are asking how to work a graphing calculator, I am neither interested or capable of helping. But I can help a bit in understanding what this function looks like, with some tricks about graphing in general.
1) Identify the domain of the function, i.e. what values of ##t## do you care about. In this case I'll guess that it's ##0 \leq t \leq \infty##. Then evaluate the function at those limits and put those points on your graph. For infinity, you can put in a really big value for ##t##. Even though you can't graph it at ##\infty##, do it and write down the value.
2) Identify factors in the function that are simple operations on a more basic function. For example ##y=x^2+2##, or ##y=10x^2##, are really just simple variations on ##y=x^2##. Don't waste too much effort on these numbers, just use as required. So from an abstract point of view your function is similar to ##y=\frac{t}{t+a}##, with ##a=200000##, just 30 times bigger.
3) Try to see how the function behaves near the extreme values, you can often approximate the function with a simpler version. For example, in this case, what is the difference between ##C(t)=\frac{30⋅t}{200000+t}## and ##C(t)=\frac{30⋅t}{200000}## when ##t \ll 200000##, for example ##t=1##, ##t=10##, ##t=100##, etc. Same for the large values (##t \gg 200000##, like ##t=10^8##), but a different approximation. This will give you two asymptotic approximate functions that will be very close to the real function at the extremes, but won't work so well in the middle.
4) Sketch those asymptotic functions (dotted lines, usually) as guidelines for where/how the function starts and ends.
5) In the middle section, where ##t \ll 200000## and ##t \gg 200000## aren't true, you'll need to calculate some values and plot them to see how the function makes the transition from one asymptote to the other. I'd start with ##t=200000##, as a good guess.
OK, now the disclaimer. This process doesn't always work. Some functions are a pain in the @##. But you'll probably recognize most of those, or figure out in this process that things aren't simple. For well behaved functions, you can just draw a smooth line to connect the points you calculated and approaching the asymptotes.
Finally, as an enticement: this process will be easier for you in the future when you've learned about calculus and other math stuff.
