math
posted by John .
u=(2 cos pi/4)i + (2 sin pi/4)j, v = (cos 3pi/2)i + (sin 3pi/2)j
find the angle theta between the two
I'm at a lost on what to do.
Respond to this Question
Similar Questions

tigonometry
expres the following as sums and differences of sines or cosines cos8t * sin2t sin(a+b) = sin(a)cos(b) + cos(a)sin(b) replacing by by b and using that cos(b)= cos(b) sin(b)= sin(b) gives: sin(ab) = sin(a)cos(b)  cos(a)sin(b) … 
Trig
Given: cos u = 3/5; 0 < u < pi/2 cos v = 5/13; 3pi/2 < v < 2pi Find: sin (v + u) cos (v  u) tan (v + u) First compute or list the cosine and sine of both u and v. Then use the combination rules sin (v + u) = sin u cos … 
algebra
Can someone please help me do this problem? 
Mathematics  Trigonometric Identities
Let y represent theta Prove: 1 + 1/tan^2y = 1/sin^2y My Answer: LS: = 1 + 1/tan^2y = (sin^2y + cos^2y) + 1 /(sin^2y/cos^2y) = (sin^2y + cos^2y) + 1 x (cos^2y/sin^2y) = (sin^2y + cos^2y) + (sin^2y + cos^2y) (cos^2y/sin^2y) = (sin^2y … 
Math
Test for symmetry with repsect to Q=pi/2, the polar axis, and the pole. r=16cos 3Q r=16cos(3pi/3 + 3h) = 16(cos3pi/2 3h sin 3pi/2 sin h) cos 3pi/2 = 0 sin 3pi/2 = 1 Not symmetrical My teacher said that this was wrong!Why? 
Math
Test for symmetry with repsect to Q=pi/2, the polar axis, and the pole. r=16cos 3Q r=16cos(3pi/3 + 3h) = 16(cos3pi/2 3h sin 3pi/2 sin h) cos 3pi/2 = 0 sin 3pi/2 = 1 Not symmetrical My teacher said that this was wrong!Why? 
math
tan theta= 15/8 and pi< theta<3pi/2 a. Sin( theta) b. cos2theta c. sin( theta  3pi/4) d. cos(theta/2) can someone explain to me how do you find the exact value for these? 
Math
Find the exact value: cos(pi/16)cos(3pi/16)sin(pi/16)sin(3pi/16) 
Math
Find the exact value: cos(pi/16)cos(3pi/16)sin(pi/16)sin(3pi/16) 
Algebra 2
What values for theta(0 <= theta <= 2pi) satisfy the equation?