can anyone give me some sums in trignometry to solve?

Question

i have got a test

Answer 1

1)x is an angle in quadrant III and sin x = -1 / 3. Find cos x.
2)x is an angle in quadrant IV and tan x = -5. Find sin x.
3)Simplify the trigonometric expression
(sin x + cos x)2 + (sin x - cos x)2
4)Find the exact value of sin(15o)
5)Simplify cos(x - pi/2)
6)Find the inverse of the linear function f.
f(x) = 3x - 2
7)Find the inverse of the quadratic function f.
f(x) = x 2 - 2x , x >= 1

For the answers to the above questions log on to www.google.co.in where u can find many such problems.

Answer 2

Calculate the area of a triangle with the sides 10, 11 and 12.

Answer 3

you need to find the height of a mountain.

You measure the angle from the ground to the top of the mountain x yards away... it is 25 degrees

You walk 100 yards toward the mountain and measure again... it is 30 degrees

Find the height of the mountain

Pretend that you can totally lay flat on the ground

Yes it is possible

Answer 4

I don't know exactly what you want so I will prove that cos 2X = 1 - 2sin² X that was offerd to you by another answerer.
Proof:
use identitiy
cos(u+v)=cos(u)cos(v)-sin(u)sin(v)
let u=v
cos(2u)=cos²u-sin²u
use identity
sin²u + cos²u = 1
cos²u=1-sin²u =>
cos(2u)=(1-sin²u)-sin²u
simplifying & replace u by x =>
cos(2x)=1-2sin²x
end of proof
-----
Now, you prove:
sin(2x)=2*sin(x)*cos(x)
using identities.
HINT
Remember that
sin(u+v)=sin(u)cos(v)+cos(u)sin(v)
------
also prove:
cos 2X = 2cos²x-1
and
cos 2X = cos²x - sin² X

Answer 5

solve cos x = x

try going through some book. that would be far better. i cannot recollect anything worthwhile (a question i mean). try S.L.Loney

Answer 6

can u solve this:-
Find the value of A if:
1/sin^2A-1/cos^2A-1/tan^2A-1/c... = -3

Answer 7

prove that cos 2X = 1 - 2sin² X

Answer 8

sin(2arctan2) = ?
i know it is a too easy question but i couldnt find anything without it :p

Answer 9

8K+j9843;jafni8u01984uj1rknqf89ioklm-+-+-**980938-12y0hjfkdjfwj[wnpufj2wqog ok there figure it out the answer is sooooooooooooooooooooo eazy

Answer 10

225.884 tan + 225848882.55478 cos ...... its not that bad we do it in honers lmao ... i'm glad it get it over with