help me please 1)if tan 1/2 x = t. find cos x.

2)what is coeficient x^3 y^2 z^5 of expanded form (x + 2y - z)^10.

3)a = (2015)^(1/2015). proof that a^(a^(a^(a^(......))) (with the number of a is 2015) < 2015.

4)Given that x^2014 - 1/(x^2014) = 7. find x^2014 + 1/(x^2014)

5)gveni P(x) = 1-x+x^2-x^3+....+x^2014-x^2015. if P(x) substitute with y and y = x+1, what is the coeficient of y^4 ?

Note by Pandoe Soekma
3 years, 5 months ago

MarkdownAppears as
*italics* or _italics_ italics
**bold** or __bold__ bold
- bulleted- list
• bulleted
• list
1. numbered2. list
1. numbered
2. list
Note: you must add a full line of space before and after lists for them to show up correctly
paragraph 1paragraph 2

paragraph 1

paragraph 2

[example link](https://brilliant.org)example link
> This is a quote
This is a quote
    # I indented these lines
# 4 spaces, and now they show
# up as a code block.

print "hello world"
# I indented these lines
# 4 spaces, and now they show
# up as a code block.

print "hello world"
MathAppears as
Remember to wrap math in $$...$$ or $...$ to ensure proper formatting.
2 \times 3 $$2 \times 3$$
2^{34} $$2^{34}$$
a_{i-1} $$a_{i-1}$$
\frac{2}{3} $$\frac{2}{3}$$
\sqrt{2} $$\sqrt{2}$$
\sum_{i=1}^3 $$\sum_{i=1}^3$$
\sin \theta $$\sin \theta$$
\boxed{123} $$\boxed{123}$$