Replacing all instances of i^2 with negative one in the new denominator gives us 64 - 4(-1). Replacing all instances of i^2 with negative one in the new numerator gives us 21 - 46 - 10(-1). Step two: Replace occurrences of i^2 with -1.Įasy, right? Just be careful not to screw up negative signs! Combining terms, this gives us 64 - 4i^2. Combining terms, this gives us 24 - 46i + 10i^2. FOIL stands for First, Outer, Inner, Last, and it’s there to remind you which terms to multiply when multiplying binomials. When you multiply two binomials, it’s critically important that you FOIL. The thing to be aware of during this step is to make sure you FOIL properly. We’re not changing the VALUE of the expression…we’re simply changing its FORM. Why are we allowed to do this? Because 8-2i / 8-2i equals one. That means we’re going to multiply the original fraction by 8-2i / 8-2i. We’re going to multiply this fraction, 3-5i / 8+2i, by the conjugate. Step one: Multiply the numerator and denominator by the conjugate Step three: Reduce (simplify) the result, if possible.Įasy as one, two, three, right? Let’s solve the problem! Remember how we said that i^2 is equal to -1? This is why that’s useful! Step two: Replace all instances of i^2 with -1. What’s the conjugate, you ask? It’s the same thing as the denominator with one critical difference: the sign in the middle gets flipped! In this problem, the denominator is 8+2i, so the conjugate is 8-2i. Step one: Multiply the numerator and denominator of this ugly fraction by the CONJUGATE of the denominator. First off, let me outline the basic process by which we’re going to solve the problem. It’s important to practice this exact operation, so pay close attention!Īny idea how to solve the problem? If not, that’s totally okay! That’s what we’re here for. Most often what they want you to do is to simplify a division expression containing imaginary numbers. Let’s learn how to do an imaginary number problem on the SATĪll right, now that we’ve defined the term “imaginary number,” we’re ready to handle a problem with imaginary numbers on the SAT. With this knowledge, you’ll be prepared to handle imaginary number questions on the SAT! But not with imaginary numbers! In the realm of imagination, it’s totally possible to square a number and get a negative answer! If you’ve taken basic math, you know that the square of every real number is a positive number, and that the square root of every real number is, therefore, a positive number. i is defined as the square root of negative one. One of the most common reactions I get when showing students how to solve a tricky SAT problem is “We never learned that in school!” Well, hopefully your school is teaching you how to handle imaginary numbers, because the SAT certainly tests you on them–and on the NO CALCULATOR math section, no less! Here, I’ll guide you through a typical SAT imaginary number problem.Īn “imaginary number” is a complex number that can be defined as a real number multiplied by the imaginary number i. SAT math has never been easy–in fact, it’s developed a relationship for being quite tricky. Do you want a higher SAT Math score - including total confidence on all SAT questions involving Imaginary Numbers? If so, check out the best SAT Math prep book ever written!
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |