# Week 3 Simplifying Radical Expressions

$2\sqrt[3]{5}$

=

=$\sqrt{-40}$

When I first do this question,I was confused by the difference of the mixed radical and entire radical. I think the most difficult part is the index part becasue there is a tube and I don’t know how to solve this. And we only learned how to simplify in Grade 10. My  understanding is that when we solve this type of question, we need to multiple all the numbers outside the root, the index and so as the radicand together. When there is a tube (3), just multiple 3, we don’t have to multiple three times becasue that’s not the exact meaning of tube. The most important thing is that we should be careful when we do the calculating.

# Week 2 Geometric Sequence

Determine $S_{10}$ for each geometric series. Give the answer to 3 decimal places. (page 49)

a)0.1+ 0.01+ 0.001+ 0.0001+…

know:$t_{1}$=0.1 ($t_{1}$ means the first one, the first place)

r=0.1( 0.01 divided by 0.1)( each term is multiplied by a constant known as the common ratio) ( to determine the common ratio, divide any  term by the preceding term)

n=10 ( a nautral number and menas the term , for instance, as the question asks to find the 10th term means n= 10)

$S_{10}$

(follow the formula, and use the caluator to caluate the 10th power)

# Week 1- My Arithmetic Sequence

1: my own arithmetic sequence: 20，22，24，26，28，30

first five numbers: 20, 22, 24, 26, 28,30

2: $t_{1}+49d=t_{50}$, d=2

20+49×2=t_{50}=118

3: \$latex t_{1}+(n-1)d=t_{n}

=20+(n-1)2

=20+2n-2

=18+2n

4:(sorry Ms Burton, I don’t know how to type the formula, but I post the process oƒ calculating the sum of the 50 terms)