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
6.974 rounded to the nearest tenth is 7.0, because 7 is more than 5, and since 9's there, we make that 6 to a 7.
Step-by-step explanation:
step 1. 12x - 15 - 12x = 7x + 20
step 2. 12x - 12x - 15 = 7x + 20 (grouping of terms)
step 3. -15 = 7x + 20 (adding like terms)
step 4. -35 = 7x (subtract 20 from both sides)
step 5. this step is incorrect.
step 6. -5 = x ( divide both sides by 7)
step 7. x = -5 (put the variable first).
Highest common prime factor is three