Answer: 0.4693877
Step-by-step explanation:
Given that:
cos x=−6/7,
From trigonometry :
Cosx + sinx = 1
Cos2x = cos(x + x)
Recall the double angle identity:
Cos2x = 2cos^2x - 1
Sin2x = 1 - 2sin^2x
Since cosx = - 6/7
Then
Cos2x = 2cos^2x - 1
Cos2x = 2cosx^2 - 1
Cos2x = 2(-6/7)^2 - 1
Cos2x = 2(36/49) - 1
Cos2x = 2 * (72/98) - 1
Cos2x = (2 * 0.7346938) - 1
Cos 2x = ( 1.4693877 - 1)
Cos2x = 0.4693877
Answer:
Step-by-step explanation:
m = 
y - 
= m( x - 
)
y = mx + b
~~~~~~~~~~~
(4, 5)
( - 6, 15)
m = (15 - 5) / ( - 6 - 4 ) = - 1
y - 5 = ( - 1)( x - 4 )
y =<em> (- 1) </em>x + <em>9</em>
Answer:
x = 2 + √3 and
x = 2 - √3
Step-by-step explanation:
Please use " ^ " to denote exponentiation: x^2 - 4x + 1 = 0.
Here you have multiple choices of methods of solution:
quadratic formula, completing the square, graphing, and so on.
If we complete the square, then: x^2 - 4x + 1 = 0 becomes
x^2 - 4x + 4 - 4 + 1 = 0, or
(x - 2)^2 = 3
Taking the square root of both sides, we get x - 2 = ±√3, so that the roots are:
x = 2 + √3 and
x = 2 - √3
