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Verify that 1 - [(sinxtanx)/(1+secx)] = cosx

User Shirlz
by
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2 Answers

3 votes

Answer:

Below.

Explanation:

Convert to sines and cosines:

1 - [(sinxtanx/ (1+ secx)]

= 1 - [(sin^2x/ cos x) / ( 1 + 1/cosx)]

= 1 - [ (sin^2 x / cos x) / (cos x + 1 / cos x)]

= 1 - [(sin^2 x / cos x) * (cosx / (cosx + 1)]

= 1 - ( sin^2 x / (cos x + 1) Using sin^2x = 1 - cos^2 x:

= 1 - (1 - cos^2x) /( cos x + 1) Using difference of 2 squares:

= 1 - [(1 + cos x)(1 - cos x)] / (1 + cos x) The (1 + cos x) is common so:

= 1 - (1 - cos x)

= 1 - 1 + cos x

= cos x.

User George Godik
by
4.0k points
3 votes

Answer:

Please see attached picture for full solution.

Other useful information:

tanx= sinx/cosx

secx= 1/cosx

Lhs= left hand side

Rhs= right hand side

Verify that 1 - [(sinxtanx)/(1+secx)] = cosx-example-1
User Jeff Tian
by
3.3k points