Biết cos a (alpha) =-3/4

Given that cos(alpha) = -3/4, we can use the Pythagorean identity to find sin(alpha):

sin^2(alpha) + cos^2(alpha) = 1
sin^2(alpha) + (-3/4)^2 = 1
sin^2(alpha) + 9/16 = 1
sin^2(alpha) = 1 - 9/16
sin^2(alpha) = 7/16
sin(alpha) = sqrt(7)/4

Next, we can find tan(alpha) by using the definition of tangent:

tan(alpha) = sin(alpha) / cos(alpha)
tan(alpha) = (sqrt(7)/4) / (-3/4)
tan(alpha) = -sqrt(7)/3

Finally, we can find cot(alpha) by taking the reciprocal of tan(alpha):

cot(alpha) = 1 / tan(alpha)
cot(alpha) = -3/sqrt(7)