Question

To prove :One plus cot square theta into tan theta by sec square theta = cot theta

Answer 1

we are given

$\frac{(1+cot^2(\theta))*tan(\theta)}{sec^2(\theta)} =cot(\theta)$

We will simplify left side and make it equal to right side

Left side:

$\frac{(1+cot^2(\theta))*tan(\theta)}{sec^2(\theta)}$

we can use trigonometric identity

$1+cot^2(\theta)=csc^2(\theta)$

we can replace it

$\frac{(csc^2(\theta))*tan(\theta)}{sec^2(\theta)}$

we know that

csc=1/sin and sec=1/cos

so, we can replace it

and we get

$\frac{cos^2(\theta)tan(\theta)}{sin^2(\theta)}$

now, we know that

tan =sin/cos

$\frac{cos^2(\theta)*sin(\theta)}{sin^2(\theta)*cos(\theta)}$

we can simplify it

and we get

$\frac{cos(\theta)}{sin(\theta)}$

we can also write it as

$=cot(\theta)$

Right Side:

$cot(\theta)$

we can see that

left side = right side

so,

$\frac{(1+cot^2(\theta))*tan(\theta)}{sec^2(\theta)} =cot(\theta)$......Answer