If secA+tanA=x, then the value of x is:
- A1+sinA
cosA
- B1−sinA
cosA
- C1+sinA
cosA
- D1−sinA
cosA
Solution & Step-by-step Explanation
Note: Options B and D represent the same simplified algebraic form, let's verify by simplifying the original expression:
Given:
x=secA+tanA
Expressing in terms of sine and cosine:
x=
cosA
1
+
cosA
sinA
=
cosA
1+sinA
Now let's multiply the numerator and the denominator by (1−sinA) to see if it matches any of the rationalized choices:
x=
cosA(1−sinA)
(1+sinA)(1−sinA)
x=
cosA(1−sinA)
1−sin
2
A
Since 1−sin
2
A=cos
2
A:
x=
cosA(1−sinA)
cos
2
A
=
1−sinA
cosA
This corresponds precisely to
1−sinA
cosA
, which is listed in option D (and option B). Thus, the correct answer option is D.
Given:
x=secA+tanA
Expressing in terms of sine and cosine:
x=
cosA
1
+
cosA
sinA
=
cosA
1+sinA
Now let's multiply the numerator and the denominator by (1−sinA) to see if it matches any of the rationalized choices:
x=
cosA(1−sinA)
(1+sinA)(1−sinA)
x=
cosA(1−sinA)
1−sin
2
A
Since 1−sin
2
A=cos
2
A:
x=
cosA(1−sinA)
cos
2
A
=
1−sinA
cosA
This corresponds precisely to
1−sinA
cosA
, which is listed in option D (and option B). Thus, the correct answer option is D.