Question

Simplify the expression cos x cot x+ sin x please select the best answer from the choices provided a.0, b.csc x, c. Tan x, d sec x

Answer 1

Answer:

$cot x = \frac{cos x}{sin x}$

$cos x \frac{cos x}{sin x} + sin x$

$\frac{cos^2 x}{sin x} +sin x$

$sin^2 x + cos^2 x =1$

Solving for $cos^2 x$ we got $cos^2 x =1 -sin^2 x$ and replacing this we got:

$\frac{1-sin^2 x}{sin x} +sin x$

$\frac{1}{sin x} -\frac{sin^2 x}{sin x} +sin x$

$csc x -sin x + sin x = csc x$

And then the best option for this case would be:

b.csc x

Step-by-step explanation:

For this case we have the following expression given:

$cos x cot x + sin x$

We know from math properties that the definition for cot is $cot x = \frac{cos x}{sin x}$

If we use this definition we got:

$cos x \frac{cos x}{sin x} + sin x$

$\frac{cos^2 x}{sin x} +sin x$

Now we can use the following identity:

$sin^2 x + cos^2 x =1$

Solving for $cos^2 x$ we got $cos^2 x =1 -sin^2 x$ and replacing this we got:

$\frac{1-sin^2 x}{sin x} +sin x$

$\frac{1}{sin x} -\frac{sin^2 x}{sin x} +sin x$

$csc x -sin x + sin x = csc x$

And then the best option for this case would be:

b.csc x