# C3 differentiation help please

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Thread starter 6 years ago
#1
Given that y=secx+tanx, find dy/dx and show that it can be written in the form 1/1-sinx

My working out:

dy/dx = secxtanx+sec2x

then I converted them
= 1/cosx (√ sec2x -1 ) + 1/cos2x

Am I on the right track? If not please help mee!
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6 years ago
#2
(Original post by queenfatso)
Given that y=secx+tanx, find dy/dx and show that it can be written in the form 1/1-sinx

My working out:

dy/dx = secxtanx+sec2x

then I converted them
= 1/cosx (√ sec2x -1 ) + 1/cos2x

Am I on the right track? If not please help mee!
Write the whole thing as one fraction: . Rewrite the denominator in terms of a familiar identity and then think about difference of two squares.
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