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Version B Question 7
3x+y=4
x^2-3y=-32
y=4-3x
x^2-3y=-32
x=-4
x=-5
y=4-3(-4)
y=4-3(-5)
y=16
y=19
(x1,y1)=(-4,16)
(x2,y2)=(-5,19)
CHECK:
3(-4)+16=4
(-4)^2=3(16)=-32
4=4
-32=-32
3(-5)+19=4
(-5)^2-3(19)=-32
4=4
-32=-32
1-cos^2(x)=sin(x)tan(x)cos(x)
=cos(x)sin(x)/cosx x sin(x)
Cos(x)cos(x)sin(x)/cos(x)
=sin(x)sin(x)
=sin^2(x)
=1-sin^2(x)
true
Solve the triangle △ABC.
A = ?
C = 32°
B = 81°
a = ?
b = 13
c = ?
32° + 81° + A = 180°
113° + A = 180
A = 67° ✓
13 / sin (81) = c / sin (32)
13 sin (32) / sin (81) = c
6.888950435 / .9876883406 = c
6.9748 = c ✓
a / sin (67) = 13 / sin (81)
a = 13 sin (67) / sin (81)
a = 12.1157 ✓
A = 67°
C = 32°
B = 81°
a = 12.1157
b = 13
c = 6.9748 ✓
Solve the triangle △ABC.
A = 90°
B = 25°
C = ?°
a = 8
b = ?
c = ?
90° + 25° + C = 180°
115° + C = 180°
C = 65° ✓
a / sin (A) = b / sin (B)
8 / sin (90) = b / sin (25)
8 * sin (25) / sin (90) = b
3.380946094 / 1 = b
3.3809 = b ✓
b / sin (B) = c / sin (C)
3.3809 / sin (25) = c / sin (65)
3.3809 * sin (65) / sin (25) = c
7.2505 = c ✓
A = 90°
B = 25°
C = 65°
a = 8
b = 3.3809
c = 7.2505 ✓
No. 7
Creative Commons image courtesy of Flickr user DeWaine Tollefsrud
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