maths.....tough thinking

[crash250]

guys....wht tan(90-x)=????

what is the answer for this tan(90-x)....how can we write it in another form?????????????????


thanks

 

[ahmed t]

tan (90-X)=1/tan(x)

 

[crash250]

why???

 

[ahmed t]

draw on a cast diagram the angles X and 90-X
find tan of X will be opposite/adjacent(yaxis/Xaxis)
if u do the same for the 90-X the opposite will be the Xaxis and the adjacent will be the Yaxis wich is the inverse of tanx
which will make it 1/tanx

 

[arlery]

What about Q1, June 2010, V1
http://www.xtremepapers.me/CIE/Internat ... _qp_11.pdf

 

[ahmed t]

well for the first one its just -k since it will be in the second quadrant which there tan is negative
second one explained above
third one
the opposite is K and the adjacent is 1 , find the hypotenus in terms of K via pythaguras theroem , and sin(X) is opp/hyp

 

[arlery]

draw on a cast diagram the angles X and 90-X
find tan of X will be opposite/adjacent(yaxis/Xaxis)
if u do the same for the 90-X the opposite will be the Xaxis and the adjacent will be the Yaxis wich is the inverse of tanx
which will make it 1/tanx

I stll dont get it. Im confused.

 

[crash250]

wht do u want be to say .....smooth thinking!!

 

[zeebujha]

think of it like this:
tan(90-x)= sin(90-x)/cos(90-x)
Now these two are easy relations:
sin(90-x)= cosx
cos(90-x)=sinx
so: tan(90-x)= cotx

 

[arlery]

Ohhhh. Now I get it =D
Thanks !!