(a) mtan refers to the slope of the tangent line. Given <em>f(x)</em> = 9 + 7<em>x</em> ², compute the difference quotient:

Then as <em>h</em> approaches 0 - bearing in mind that we're specifically considering <em>h</em> <em>near</em> 0, and not <em>h</em> = 0 - we can eliminate the factor of <em>h</em> in the numerator and denominator, so that

and so the slope of the line at <em>P</em> (0, 9), for which we take <em>x</em> = 0, is 0.
(b) The equation of the tangent line is then <em>y</em> = 9.
Equation: 
Since there aren't any like terms and it can't be factored, your answer would be:

Hope this answer helped you!
For this case we have that by definition of trigonometric relations that the sine of an angle is equal to the opposite leg to the angle on the hypotenuse. That is to say:

Clearing the value of "a":

Rounding off we have:
17.7
Answer:
Option B
A quadratic equation may be expressed in vertex form as:
y = a(x - h)² + k, the vertex being (-h , k)
For option A, the vertices are visibly different. (-4 , 0) and (4 , 0)
For B, the graphs' vertices are the same, (0 , 0).
For C, the vertices (can be obtained by differentiating and putting equal to 0) are (0 , -4) and (0 , 4)
For D, the vertices are (4 , 0) and (0 , 4)
Thus, the answer is B.