Homework Sourse1 If sintheta 713 and theta is in quadrant 2 find costheta 2
1. If sin(theta)= 7/13 and theta is in quadrant 2, find cos(theta).
2. Suppose that tan(t)= -11/4 and that t is in quadrant 1. Find the exact value of sec(t).
Solution
1. If sin(theta)= 7/13 and theta is in quadrant 2, find cos(theta).
cos(theta) = - sqrt( 1- sin^2(theta) [ cos(theta) is +ve in QII]
= -sqrt( 1- (7/13)^2 0
= - sqrt(120/169) = -2sqrt(30)/13
2. Suppose that tan(t)= 11/4 and that t is in quadrant 1. Find the exact value of sec(t).
If t is quadrant 1 then all trig functions tant , cost ,sint would be +ve
hypotenuse of right angled triangle = sqrt(11^2 +4^2)
= sqrt(137)
sect = 1/cost = sqrt(137)/4
