21 squared 2
Step-by-step explanation:
Answer:
{0, 150} degrees
Step-by-step explanation:
Given 2cos^2x-cost-1=0, let's simplify this problem by temporarily replacing cos x with y:
2y^2 - y -1 = 0
This can be solved by factoring: (2y + 1)(y - 1) = 0. From this we get two solutions: y = -1/2 and y = 1.
Remembering that we let y = cos x, we now solve:
cos x = -1/2 and cos x = 1.
Note that cos x = 1 when x = 0 and the "adjacent side" coincides with the hypotenuse.
cos x = -1/2 when the hypotenuse is 2 and the "adjacent side" is -1. This has two solutions between 0 and 360 degrees: 150 degrees and 270 degrees.
Four answer choices are given. Both (a) (0 degrees) and (b) (150 degrees) satisfy the original equation. Thus, the solution set is {0, 150} (degrees).
Answer:
no
Step-by-step explanation:
1/7 is positive, -5 is negative. Negative is less than positive
Answer:
y= -2x
Step-by-step explanation:
The equation of a line is usually written in the form of y=mx+c, where m is the gradient and c is the y-intercept.
Given that the slope is -2, m= -2.
subst. m= -2 into the equation:
y= -2x +c
To find the value of c, substitute a coordinate.
When x= -4, y=8,
8= -2(-4) +c
8= 8 +c (expand)
c= 8-8 (-8 on both sides)
c=0 (simplify)
Thus, the equation of the line is y= -2x.
