Question

Найдите cos a, если sin а=0,8 и π/2⩽ а ⩽ π

Answer 1

Ответ:

Объяснение: cosα=±√1-sin²α, α∈2 чтв, cosα<0

cosα=-√1-0,64 =-√0,36=-0,6.

Answer 2

To find the value of cos(a) given that sin(a) = 0.8 and π/2 ≤ a ≤ π, we can use the Pythagorean trigonometric identity:

sin^2(a) + cos^2(a) = 1

Since we know sin(a) = 0.8, we can plug it into the equation and solve for cos(a):

(0.8)^2 + cos^2(a) = 1 0.64 + cos^2(a) = 1 cos^2(a) = 1 - 0.64 cos^2(a) = 0.36

Now, to find cos(a), we take the square root of both sides. Since 0.36 is positive, we take the positive square root:

cos(a) = √(0.36) cos(a) = 0.6

So, cos(a) = 0.6 when sin(a) = 0.8 and π/2 ≤ a ≤ π.