Please help me 20 points Where does the Pythagorean Identity sin2 Θ + cos2 Θ = 1 come from? Given the Cos Θ = 4/5, how would you use it to find the sine and tangent values of the angle? Explain.

Step-by-step explanation:

Kindly refer to the attached image of a right angled .

Let

Sides BC = a

AB = c and

AC = b respectively.

To prove:

Proof:

Using Sine and Cosine values:

As per Pythagorean theorem:

Considering the LHS of :

Now, using equation (1):

Hence, proved that :

Now, we are given that:

To find, sine and cosine values of the angle i.e. and

Using :

We know that:

55/i dont know i do it for the points

step-by-step explanation:

step-by-step explanation:

the original amount doesn't ''re just looking for the time it takes for 1/2 of the substance to we have

(1/2) =)     take the ln   of both sides

ln (1/2)   = )   and we can write

ln(1/2) = ) lne     and lne   = 1     so we have

ln(1/2) = -.1092t     divide both sides by -.1092

t = ln(1/2)/-.1092 = about 6.347 days = about 6.3 days (rounded)