SOLUTION: I have three math problems I don't even know where to start. If you could help please. 1) sec x (csc x - cot x * cos x) = tan x 2) cos^2 x + tan^2 x cos^2 x = 1 For proble

Algebra ->  Rational-functions -> SOLUTION: I have three math problems I don't even know where to start. If you could help please. 1) sec x (csc x - cot x * cos x) = tan x 2) cos^2 x + tan^2 x cos^2 x = 1 For proble      Log On


   



Question 122288: I have three math problems I don't even know where to start. If you could help please.
1) sec x (csc x - cot x * cos x) = tan x
2) cos^2 x + tan^2 x cos^2 x = 1
For problems 1&2 x is theta
3) (cscx-sinx)^2= cot^2 x - cos^2 x

Answer by algebrapro18(249) About Me  (Show Source):
You can put this solution on YOUR website!
basically what you are trying to do here is prove that the left hand side and the right hand side are the same thing. You use trig identities to do this.

NOTE: for this to work out neatly I had to use the formula part of this site and it didn't let me do things with your notation so you need to know that:

tan^2 x = (tan x)^2
sin^2 x = (sin x)^2
cos^2 x = (cos x)^2
cot^2 x = (cot x)^2

1)
sec+x+%28csc+x+-+cot+x+%2A+cos+x%29+=+tan+x+ --> Change cot x into cos x / sin x
sec+x%28csc+x+-+%28%28cos+x%29%2F%28sin+x%29+%2A+cos+x%29%29+=+tan+x+ --> get a common denominator
sec+x%28%281%2Fsin+x%29+-+%28%28cos+x%29%5E2%2F%28sin+x%29%29%29+=+tan+x+ --> subtract
sec+x%28%281-%28cos+x%29%5E2%29%2F%28sin+x%29%29+=+tan+x+ --> 1 - cos^2 x = sin^2 x
sec+x%28%28sin+x%29%5E2%2F%28sin+x%29%29+=+tan+x+ --> divide
sec+x%28sin+x%29+=+tan+x+ --> sec x = 1/cos x
%281%2Fcos+x%29+%2A%28sin+x%29+=+tan+x+ --> multiply
+sinx+%2F+cos+x+=+tan+x+ --> simplify
+tan+x+=+tan+x+

2)
%28cos+x%29%5E2+%2B+%28tan+x%29%5E2+%2A+%28cos+x%29%5E2+=+1+ -->factor out a cos^2 x
%28cos+x%29%5E2+%2A%281+%2B+%28tan+x%29%5E2%29+=+1+ --> 1 + tan^2 x = sec^2 x
%28cos+x%29%5E2+%2A%28sec+x%5E2%29+=+1+ --> sec ^2 x = 1 / cos^2 x
%28cos+x%29%5E2+%2A+1%2F%28cos+x%29%5E2+=+1+ --> multiply and simplify
+1+=+1+

I don't know how to do the third one