Top answers

What is a vector?

A quantity may be a scalar (just a magnitude, just a number) or a vector, with magnitude and direction. For example, speed is a measure of how fast something is going, but velocity is a measure of how fast s...
PC
Answered by Patrick C. • Physics tutor
3648 Views

How do I differentiate an algebraic expression? (e.g. y=3x^4 - 8x^3 - 3) [the ^ represents x being raised to a power]

y=3x 4 -8x 3 -3 Let's say we want to calculate dy/dx. For a term A x n , the differential with respect to x is An x n-1 . For a constant value, we can say that n=0 because x 0 =1. This means that when you di...
PC
Answered by Patrick C. • Maths tutor
3997 Views

Work out the nth term of the sequence 3, 7, 11, 15, ...

This is an example of an arithmetic series because each term is +4 from the previous term.This means for the "nth term" we start with +4n.Now we take a specific term from the sequence e.g. 3 (1st t...
AL
Answered by Alice L. • Maths tutor
5597 Views

How do I expand double brackets? E.g. (4x+7)(3x+5)

In order to expand the brackets, we need to ensure that EVERYTHING in the left bracket is multiplied by EVERYTHING in the right bracket. There are 3 methods for helping us to times out the brackets. These ar...
SA
Answered by Shona A. • Maths tutor
6925 Views

Elemental analysis of a carbohydrate X showed the sample contained 48.7 % carbon and 8.1 % hydrogen by mass. Find the empirical formula of X.

These sorts of questions can look difficult, but if you learn the steps needed to solve them then they are all very similar. Step 1: Since we are told that X is a carbohydrate, we know that the only other co...
JB
Answered by Jack B. • Chemistry tutor
2237 Views