What is goalseek on exel?

Answer 1

Goalseek is a tool that lets you find the necessary input values into an equation to get the desired answer. Consider it a kind of "optimization" tool; in other words, if you know what the answer should be, you can tell Goalseek to find what input value will get the closest result to the known answer. It works like this, consider the example of < 2x + 3 = y >: now say that you need y to equal 15, but you want to find what then is the value of x (with this simple example, of course you can just rearrange and solve, but pretend for the moment that that is not possible). What you do in Excel is first make some cell an arbitrary input "x" value... so say in cell C3 put 10 (any number will do for now... with more complex expressions it sometimes becomes necessary to choose this arbitrary value more carefully). Now in another cell (say D3) write the formula for "y", i.e write "=2*$C$3+3"... the value of that cell should now be 23. Now choose Tools->Goalseek, and in "Set Cell" put D3, in "To Value" put 15, and in "By changing cell" put C3. Hit Ok. Excel will iterate until it settles on the correct value, in this case 6. You can try this with all kinds of (even very, very complicated) expressions, and this tool can also be incorporated into macros so that Excel can Goalseek whole columns of data for you.