If cscA−cotA=x, then the value of x is:
- A\frac{\sin A}{1-\cos A}
- B\frac{\sin A}{1+\cos A}
- C\frac{\sin A}{1+\cos A}
- D\frac{\sin A}{1-\cos A}
Solution & Step-by-step Explanation
Given expression:
x=cscA−cotA
Expressing cscA and cotA in terms of sinA and cosA:
cscA=
sinA
1
cotA=
sinA
cosA
Substitute these values:
x=
sinA
1
−
sinA
cosA
x=
sinA
1−cosA
To match the options, multiply the numerator and denominator by (1+cosA):
x=
sinA(1+cosA)
(1−cosA)(1+cosA)
Using the algebraic identity (a−b)(a+b)=a
2
−b
2
:
x=
sinA(1+cosA)
1−cos
2
A
Since 1−cos
2
A=sin
2
A:
x=
sinA(1+cosA)
sin
2
A
x=
1+cosA
sinA
x=cscA−cotA
Expressing cscA and cotA in terms of sinA and cosA:
cscA=
sinA
1
cotA=
sinA
cosA
Substitute these values:
x=
sinA
1
−
sinA
cosA
x=
sinA
1−cosA
To match the options, multiply the numerator and denominator by (1+cosA):
x=
sinA(1+cosA)
(1−cosA)(1+cosA)
Using the algebraic identity (a−b)(a+b)=a
2
−b
2
:
x=
sinA(1+cosA)
1−cos
2
A
Since 1−cos
2
A=sin
2
A:
x=
sinA(1+cosA)
sin
2
A
x=
1+cosA
sinA