Answer:
cos 2 x=1-sin^2 x
Step-by-step explanation:
x=-135°
cos 2x=cos (-270)=cos (-270+360)=cos 90=0
or cos 2x=1-2sin ²x=1-2(sin (-135))²
=1-2(-sin 135)²
=1-2(sin 135)²
=1-2(sin (180-45))²
=1-2(sin²45)
=1-2 (\frac{1}{\sqrt{2}})²
=1-1
=0
If you debit one side you have to debit the other. what you do to one side you must do to the other.
We'll solve this equation in order to find the score of the 4th test, which we denote with x.

. Solving it we find that x=63. And it is the final answer for this problem.
Formula for combinations:
(n!)/(r!(n-r)!)
For you, this is:
10!/(5!(10-5)!) = 10!/5!5! = (10•9•8•7•6•5•4•3•2)/(5•4•3•2)(5•4•3•2) = (10•9•8•7•6)/(5•4•3•2) = 30240/120=252 different ways.
Answer:
C). Zero
Step-by-step explanation:
This is a pretty simple question.
Any number multiplied by zero will be zero, and zero cannot have a positive or negative sign, which is why zero has its own sign, which is known as the Sign of Zero.