Math: how to graph a line
When you tutor math, you know that everyone from grade 9 up needs to know this. Suppose you need to graph 2x – 7y = 21. There are two basic methods: the slope-y intercept method, and the intercepts method. Today, …
Category: math
Math: decimals to fractions
Tutoring middle school math, you get asked how to convert decimals to fractions. The math tutor tells some obvious – and some less obvious – methods. Converting a terminating decimal (one that ends) to a fraction is easy: Step 1) …
Math: Radians, Part II
Tutoring math, you deal with degree-to-radian conversions. The math tutor continues on the topic of radians, picking up where he left off last July. To know what a radian is, see my post here. In math 12, radians – …
Math: Constant Calculations on the TI-30XA
Tutoring math, you handle all kinds of calculators. The math tutor continues with constant calculations: this time, we hear Texas Instruments’ side of the story. The TI-30XA is extremely similar to the calculator I used in high school twenty five …
Math: Using constants on the Casio fx-260Solar
Tutoring math, calculator use is perennial. The math tutor introduces a nifty trick for the Casio fx-260Solar. In physics, you often have a constant in a formula. An obvious example is F=mg, where g=9.8m/s^2 High school physics students use the …
Math: A counting problem
Tutoring math 12 and some university courses, you get asked about counting. The tutor opens the discussion with a couple of examples. Questions that ask, “How many ways can people be lined up for a photograph” or “how many five-card …
Math: Systems of equations: a word problem
Tutoring math, you revisit this type of problem often. The math tutor gives a quick reminder just ahead of exams. Here’s the problem: A saleswoman gets paid a base monthly salary plus commission. One month she sells $50 000 and …
Math: a little more on factoring
Tutoring high school math, you might be in review mode now. The math tutor brings up a couple of factoring instances. Instance 1: Suppose you need to factor -2x^2 + 4x + 70. How would you proceed? Solution: First, you …
Math: factoring difference of cubes
The math tutor continues with factoring cubes. Tutoring calculus, this formula is another standby. Let’s turn to factoring x^3 – 64. Realizing that 64=4^3, you actually are facing x^3-4^3 You need the formula a^3 – b^3=(a-b)(a^2 + ab + b^2) …
Math: factoring sum of cubes
Tutoring high school math, you rarely see this; it comes up often, however, in calculus. The tutor offers a light treatment. How do you factor x^3 + 125? You need the following formula: a^3 + b^3 = (a + b)(a^2 …