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AS Math queries

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nid404:

--- Quote from: spiderman on September 03, 2009, 01:54:51 pm ---Find all the values of @ in the interval -180<=@<=180
1)4sin@=5cos@
2)2sin@=1/sin@


Pls help me wit these sums
Guys i really suck in trignometry...wud b glad if u cud post some sites which demonstrate how to solve the type of sums that cum in the as and a level papers..... :)

--- End quote ---

I'll answer the second one in a while
for the first 1
4sintheta/5costheta=1
u r aware of
sintheta/costheta= tan theta
so
4sintheta/5costheta=0.8tantheta
0.8tantheta=1
tan theta=1 / 0.8
theta= tan-1(1/ 0.8)
theta=51.3
and 51.3-180=-128.7

hope u got it

spiderman:
Thanks a lot buddy

nid404:
second 1
2sin theta=1/sin theta
2=1/sin2theta
2sin2theta=1
sin2theta=1/2
sin theta= root of 1/2
theta= sin-1(1/2)1/2
theta= 45
and 45-180=-135

hope this helps and sorry for the delay

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