Sin theta upon 1 + cos theta + 1 + cos theta upon sin theta is equals to 2 cosec theta prove

Step-by-step explanation:

I'll use x  instead of theta.

So we have:

sin x / ( 1 + cos x) + (1 +cos x) / sinx

The LCM is sin x(1 + cos x) so we have

sin^2 x + (1 + cos x)^2 /  sin x(1 + cos x)

= sin^2 x + cos^2x + 2 cos x + 1 /  sin x(1 + cos x)

Now sin^2x + cos^2x = 1 so:

= 2 + 2 cos x /  sin x(1 + cos x)

= 2(1+ cos x) /  sin x(1 + cos x)

The 1 + cos x is common so we have:

2 / sin x

= 2 cosec x.

problem:

f(x) = - 2/3x + 5; f(5/2)

substitute 5/2 in for x:

f(5/2) = -2/3(5/2) + 5

simplify the right side:

f(5/2) = -5/3 + 5

f(5/2) = 10/3

f(5/2) = 10/3

i hope this !