if cosine A=0•8 find sine B
I guess you mean find sin A because I have no idea what B is
cos^2 + sin^2 = 1
0.8^2 + sin^2 = 1
sin^2 = 1-0.64 = 0.36
sin = +/- sqrt(0.36)
as shown above, sinA = ±0.6
or, you can see that if you draw a triangle, it is just a scaled-down 3-4-5 triangle. so if sinA = 4/5, cosA = 3/5.
To find the value of sine B, given that cosine A is 0.8, we first need to determine the value of angle A.
The relationship between sine and cosine is given by the Pythagorean Identity: sin^2(A) + cos^2(A) = 1. Therefore, we can solve for sin(A) using the following equation:
sin(A) = √(1 - cos^2(A))
sin(A) = √(1 - 0.8^2)
sin(A) = √(1 - 0.64)
sin(A) = √(0.36)
sin(A) = 0.6
Now that we have found the value of sin(A) to be 0.6, we can move on to finding the value of angle B.
By using the relationship between the sine of an angle and the angle itself, we can express sin(B) as sin(B) = 0.6. However, without more information, it is not possible to determine the exact value of angle B.
Please note that B could have multiple possible values since sine is a periodic function with a period of 360 degrees or 2π radians. Therefore, additional information would be needed to determine the exact value of angle B.