Find the value of 2cosx+1=0;0 less than x less than 360°
1 answer:
Answer:
120°; 240°
Step-by-step explanation:
Let's first solve for :
At this point it's just a matter of drawing a circle, and mark where the angle is(please excuse my paint skills, but free hand drawing would be even worse). Red line, is
on the cosines, and both the green and blue lines are valid solutions. The green line is a quarter of a circle, plus 30°, or 120°. The blue one is 3/4 of a circle, minus 30 degrees, or 240°.
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In the plane, we have
everywhere. So in the equation of the sphere, we have
which is a circle centered at (2, -10, 0) of radius 4.
In the plane, we have
, which gives
But any squared real quantity is positive, so there is no intersection between the sphere and this plane.
In the plane,
, so
which is a circle centered at (0, -10, 3) of radius .
