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6 answers

5

2006-07-15 18:37:49 · answer #1 · answered by MnKLmT 4 · 0 0

This is an identity to prove, not an equation to solve. They're quite different.

Remember sec is 1/cos and tan is sin/cos.
So sec A(1 - sin A)(sec A + tan A) =
(sec A - tan A)(sec A + tan A) =
sec² A - tan² A =
1

2006-07-16 01:42:50 · answer #2 · answered by Philo 7 · 0 0

You want us to simplify, or solve for A?

Notice that sec A=1/(cos A), and tan A=(sin A)/(cos A)

Now replace all of the sec A, and tan A:

(sec A)(1-sin A)(sec A+tan A)=(1/cos A)(1-sin A)(1/cos A+ sin A/cos A)=(1/cos A)^2(1-sin A)(1+sin A)= (1/cos A)^2(1-(sin A)^2)= (1/cos A)^2(cos A)^2=1. Thus this is true for all A. (therefore this is a type of trig identity.)

2006-07-16 01:40:14 · answer #3 · answered by Eulercrosser 4 · 0 0

sec A(1-sin A)(sec A+tan A)=1
(sec A-tan A)(sec A + tan A)=1
sec² A - tan² A=1
(1-sin² A)/cos² A=1
cos² A/cos² A=1
1=1

Q.E.D.

2006-07-16 01:47:25 · answer #4 · answered by Pascal 7 · 0 0

consider the lhs
multiply sec a inside the brackets
u get
(sec a - tan a)( sec a + tan a)
ie sec ^2 a - tan^2 a
ie 1 + tan^2 a - tan^2 a
ie 1
lhs = rhs
this is not a question on solving its a question on proving the lhs = rhs

if it were a question on solving the answer would be all real numbers....as this isn an identity......which is true for all values

2006-07-16 01:46:35 · answer #5 · answered by coolelectromagnet 2 · 0 0

sec A (1- sin A)(sec A + tan A)

= 1/cos A(1-sin A)(sec A + tan A)
= (1/cos A - tan A)(sec A + tan A)
= (sec A - tan A)(sec A + tan A)
= sec^2 A - tan^2 A
= 1

2006-07-16 01:43:30 · answer #6 · answered by Anonymous · 0 0

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