Without using a calculator, simplify the following expression:

[tex]\[
\frac{\sin \left(180^{\circ}-x\right) \tan \left(90^{\circ}-x\right)}{\cosec\left(90^{\circ}-x\right) \cos \left(360^{\circ}-x\right) \cot \left(180^{\circ}+x\right)}
\][/tex]



Answer :

To solve the expression:
[tex]\[ \frac{\sin(180^\circ - x) \tan(90^\circ - x)}{\csc(90^\circ - x) \cos(360^\circ - x) \cot(180^\circ + x)}, \][/tex]
we will use trigonometric identities.

1. Simplify [tex]\(\sin(180^\circ - x)\)[/tex]:

Using the co-function identity:
[tex]\[ \sin(180^\circ - x) = \sin x \][/tex]

2. Simplify [tex]\(\tan(90^\circ - x)\)[/tex]:

Using the identity:
[tex]\[ \tan(90^\circ - x) = \cot x \][/tex]

3. Simplify [tex]\(\csc(90^\circ - x)\)[/tex]:

Using the co-function identity:
[tex]\[ \csc(90^\circ - x) = \sec x \][/tex]
and since [tex]\(\csc x\)[/tex] is the reciprocal of [tex]\(\sin x\)[/tex], likewise [tex]\(\sec x\)[/tex] is the reciprocal of [tex]\(\cos x\)[/tex]:
[tex]\[ \csc(90^\circ - x) = \frac{1}{\cos x} \][/tex]

4. Simplify [tex]\(\cos(360^\circ - x)\)[/tex]:

Using the co-function identity:
[tex]\[ \cos(360^\circ - x) = \cos x \][/tex]

5. Simplify [tex]\(\cot(180^\circ + x)\)[/tex]:

Using the identity:
[tex]\[ \cot(180^\circ + x) = -\cot x \][/tex]

Now substitute these identities back into the original expression:

[tex]\[ \frac{\sin x \cdot \cot x}{\left(\frac{1}{\cos x}\right) \cos x \cdot (-\cot x)} \][/tex]

Simplify the numerator and denominator:

[tex]\[ = \frac{\sin x \cdot \cot x}{\left(\frac{1}{\cos x}\right) \cos x \cdot (-\cot x)} = \frac{\sin x \cdot \cot x}{\frac{\cos x}{\cos x} \cdot (-\cot x)} = \frac{\sin x \cdot \cot x}{1 \cdot (-\cot x)} = \frac{\sin x \cdot \cot x}{-\cot x} = -\sin x \][/tex]

Thus, the final simplified expression is:

[tex]\[ -\sin x \][/tex]