Option C:
x = 90°
Solution:
Given equation:
<u>To find the degree:</u>
Subtract 1 + cos²x from both sides.
Using the trigonometric identity:
Let sin x = u
Factor the quadratic equation.
u + 2 = 0, u – 1 = 0
u = –2, u = 1
That is sin x = –2, sin x = 1
sin x can't be smaller than –1 for real solutions. So ignore sin x = –2.
sin x = 1
The value of sin is 1 for 90°.
x = 90°.
Option C is the correct answer.
Answer:
x = 33/5
Step-by-step explanation:
4x+x-15+3-8=13
Combine like terms
5x -20 = 13
Add 20 to each side
5x-20+20 = 13+20
5x =33
Divide by 5
5x/5 = 33/5
x = 33/5
Answer:
x = -7 2/3, y = 1 1/3 and z = 5 1/3.
Step-by-step explanation:
2x+4y+3z=6 ..... 1
x-2y+z=-5 ...... 2
-x-3y-2z=-7 .......3
Add equations 2 and 3 to eliminate x:
-5y - z = -12 .....4
Multiply equation 2 by - 2:
-2x + 4y - 2z = 10
Add this to equation 1:
8y + z = 16 ........ 5
Now add equation 4 to equation 5:
3y = 4
y = 4/3 = 1 1/3.
Now find z by substituting for y in equation 4:
-5(4/3) - z = -12
z = 12 - 20/3
z = 36/3 - 20/3 = 16/3 = 5 1/3.
Finally, we find x by substituting for y and z in equation 1:
2x + 4*4/3 + 3*16/3 = 6
2x = 6 - 16/3 - 16
2x = 18/3 - 16/3 - 48/3 = -46/3
x = 23/3 = 7 2/3.
x should equal -2 and y should equal -3 to solve this i multiplied the first equation by 2 then got rid of the 4y and -4y then i added the 14x to the 9 equaling 23x and added the -40 to the -6 which became 23x=-46 i solved this getting -s for x, then i plugged that into the equations to get y which was -3
