knowledge : point (-3,-4)is on the terminal arm of an angel (alpha) in stander position.verify that (sin alpha)2 + (cos alpha )2 =1

Answer 1

FYI: angle, standard

hypotenuse h = √(3^2+4^2) = √25 = 5

sinθ = y/h = -4/5
cosθ = x/h = -3/5

sin^2θ + cos^2θ = (-3/5)^2 + (-4/5)^2 = 9/25 + 16/25 = 25/25 = 1