If
1−sinA
cosAcotA
=x, then the value of x is
- A1−cscA
- B1+cscA
- C1+secA
- D1−secA
Solution & Step-by-step Explanation
Given expression:
x=
1−sinA
cosAcotA
Substitute cotA=
sinA
cosA
:
x=
1−sinA
cosA⋅
sinA
cosA
=
sinA(1−sinA)
cos
2
A
Using the identity cos
2
A=1−sin
2
A:
x=
sinA(1−sinA)
1−sin
2
A
Factorise the numerator as a difference of squares (a
2
−b
2
=(a−b)(a+b)):
x=
sinA(1−sinA)
(1−sinA)(1+sinA)
Cancel out the common term (1−sinA) from the numerator and denominator:
x=
sinA
1+sinA
Split the fraction:
x=
sinA
1
+
sinA
sinA
x=cscA+1⟹1+cscA
x=
1−sinA
cosAcotA
Substitute cotA=
sinA
cosA
:
x=
1−sinA
cosA⋅
sinA
cosA
=
sinA(1−sinA)
cos
2
A
Using the identity cos
2
A=1−sin
2
A:
x=
sinA(1−sinA)
1−sin
2
A
Factorise the numerator as a difference of squares (a
2
−b
2
=(a−b)(a+b)):
x=
sinA(1−sinA)
(1−sinA)(1+sinA)
Cancel out the common term (1−sinA) from the numerator and denominator:
x=
sinA
1+sinA
Split the fraction:
x=
sinA
1
+
sinA
sinA
x=cscA+1⟹1+cscA