Selma is buying a cell phone for business. The regular price of the phone is $179. If she buys the phone at 20% discount how muc
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For this, we will be using the quadratic formula, which is , with a=x^2 coefficient, b=x coefficient, and c = constant. Our equation will look like this:
Firstly, solve the multiplications and the exponents:
Next, do the addition:
Next, your equation will be split into two: . Solve them separately, and your answer will be
First lets see the pythagorean identities
So if we have to solve for sin theta , first we move cos theta to left side and then take square root to both sides, that is
Now we need to check the sign of sin theta
First we have to remember the sign of sin, cos , tan in the quadrants. In first quadrant , all are positive. In second quadrant, only sin and cosine are positive. In third quadrant , only tan and cot are positive and in the last quadrant , only cos and sec are positive.
So if theta is in second quadrant, then we have to positive sign but if theta is in third or fourth quadrant, then we have to use negative sign .