pre calc
posted by Danika .
suppose beta is an angle in the second quadrant and tan beta=2. Fine the exact vaule of sin beta and cos beta

draw a rightangled triangle in the second quad
so that tan B = 3/1, that is make the opposite 3 and the adjacent 1, thus the hypotenuse is √10
so y=3, x = 1, r=√10
sinB = 3/√10, cosB = 1/√10