Answer:
√2(√3 - 1)/4
Step-by-step explanation:
To find an exact value for Cos75°, we use the compound angle formula. Since 75° = 45° + 30°, Cos75° = Cos(45° + 30°).
Using Cos(A + B) = CosACosB - SinASinB where A = 45° and B = 30°,
Cos75° = Cos(45° + 30°) = Cos45°Cos30° - Sin45°Sin30°
Now Cos45° = Sin45° = 1/√2 = √2/2, Cos30° = √3/2 and Sin30° = 1/2.
Substituting these values into the above equation, we have
Cos75° = Cos(45° + 30°)
= Cos45°Cos30° - Sin45°Sin30°
= √2/2 × √3/2 - √2/2 × 1/2
= √6/4 -√2/4
= √2(√3 - 1)/4
Answer:
Rosaria purchased 50 bracelets and 70 necklaces
Step-by-step explanation:
Let the number of bracelets be b and the number of necklaces be n
b + n = 120 •••••(i)
Secondly;
10b + 11n = 1270 ••••(ii)
Total cost of b bracelets at 10 per 1 is 10b
Total cost of n bracelets at 11 per 1 is 11n
Adding both gives 1270
From i, b = 120-n
Substitute this into ii
10(120-n) + 11n = 1270
1200 - 10n + 11n = 1270
n = 1270-1200
n = 70
b = 120-n
b = 120-70
b = 50
Answer:
(-2/7, 2/3)
step-by-step explanation:
-7x + 3y = 2
x = 0
-7(0) + 3y = 2
3y = 2
/3 /3
y = 2/3
y = 0
-7x + 3(0) = 2
-7x = 2
/-7 /-7
x = -2/7
(-2/7, 2/3)
Its the third option (2, 4)
<h3>Given</h3>
Three numbers are n, 8n, and (100+n).
Their total is 690.
<h3>Find</h3>
the three numbers
<h3>Solution</h3>
n + 8n + (n+100) = 690
10n + 100 = 690 . . . . . . . simplify
10n = 590 . . . . . . . . . . . . subtract 100
n = 59
8n = 472
n +100 = 159
The three numbers are 59, 472, and 159.