Cos 157.5º=-cos (180º-157.5º)=-cos 22.5=-cos(45/2)
cos Ф/2=⁺₋√((1+cosФ)/2).
In this case 157.5º is in the second quadrant, therefore we use the following equation:
cos Ф/2=-√((1+cosФ)/2). (we will have a negative number)
cos 157.5º=-cos (45/2)=-√((1+cos 45º)/2)
=-√((1+√2/2)/2)
=-√((2+√2)/4)
=-√(2+√2) / 2 (≈-0.92387...)
Answer: cos 157.5º= -√(2+√2) / 2
Answer:
5. 9 8. 
Step-by-step explanation:
a²+b²=c²
so for #5 12²+b²=15²
144+b²=225 (subtract 144 from both sides)
b²=81
b=9
For #8
9²+b²=11²
81+b²=121 (subtract 81 from both sides)
b²=40
b=
=
Answer:
75
Step-by-step explanation:
The measure of two supplementary angles = 15:21
The angles are 15x , 21x
15x + 21x = 180 {Supplementary}
36x = 180
x = 180/36
x = 5
Smallest angle = 15 * 5 = 75
Answer:
1.07 (15 + x) = 42.80
Step-by-step explanation:
Given data
CD= $15
Let the cost of the video game be x
The total cost= 15+x
Hence the equivalent expression is
1.07 (15 + x) = 42.80
open bracket
16.05+1.07x= 42.80
42.80-16.05= 1.07x
26.75=1.07x
x= 26.75/1.07
x= 25
Check
7% tax for CD
=0.07*15
=1.05
total =1.05+15
=$16.05
7% tax for Video game
=0.07* 25
=1.75
total =1.75+25
=$26.75
In all
=26.75+16.05
=$42.8
Ivan forgot to follow PEMDAS
Division first
12/3 = 4
4 x 2 = 8
8 + 8 = 16
Hope this helps!
