trig
posted by killie .
I am very confused about the concepts of..
sin è = sin(180  è)
sin (180 + è)= sinè
tan (180  è) = tanè
and how the final answer was found in this problem...
Find cos 510:
cos510=cos(54030)
=cos30
=s.r3/2
i don't understand how we went from cos 30 to s.r3/2 ?
Respond to this Question
Similar Questions

trig
Reduce the following to the sine or cosine of one angle: (i) sin145*cos75  cos145*sin75 (ii) cos35*cos15  sin35*sin15 Use the formulae: sin(a+b)= sin(a) cos(b) + cos(a)sin(b) and cos(a+b)= cos(a)cos(b)  sin(a)sin)(b) (1)The quantity … 
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 … 
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 … 
TRIG!
Posted by hayden on Monday, February 23, 2009 at 4:05pm. sin^6 x + cos^6 x=1  (3/4)sin^2 2x work on one side only! Responses Trig please help!  Reiny, Monday, February 23, 2009 at 4:27pm LS looks like the sum of cubes sin^6 x + cos^6 … 
Trig
4. Asked to simplify the expression sin(180−è), Rory volunteered the following solution: sin(180−è) = sin 180−sin è, and, because sin 180 is zero, it follows that sin(180−è) is the same as −sin è. … 
Trig
A. Find simpler, equivalent expressions for the following. Justify your answers. (a) sin(180 + è) (b) cos(180 + è) (c) tan(180 + è) B. Show that there are at least two ways to calculate the angle formed by the vectors [cos 19, sin … 
trigonometry
is this correct? sin 255degrees 225 = 180 + 45 sin(225) = sin(180 + 45) = sin(180)cos(45) + cos(180)sin(45) sin(225) = 0 + (1)(sqrt2/2) sin(225) = (sqrt2)/2 
trig
solve for the equation x sin x= .35 180<x<270 sin x= .2 90<x<180 cos x = .72 180< x<270 please explain, thanks :) 
Maths
1) Simplification (trigonometric ratios of allied angles)? 
math
tan(180x)sin(360x)cos90x)cos(x)/sin(x180)cos(450+x)tan(180x)