Answer:
<em>A.</em>
<em>The student made an error in step 3 because a is positive in Quadrant IV; therefore, </em>
<em />
Step-by-step explanation:
Given



Required
Where and which error did the student make
Given that the angle is in the 4th quadrant;
The value of r is positive, a is positive but b is negative;
Hence;

Since a belongs to the x axis and b belongs to the y axis;
is calculated as thus

Substitute 


Rationalize the denominator


So, from the list of given options;
<em>The student's mistake is that a is positive in quadrant iv and his error is in step 3</em>
Answer:
e=-7
Step-by-step explanation:
<u><em>Answer:</em></u>
AC = 10sin(40°)
<u><em>Explanation:</em></u>
The diagram representing the question is shown in the attached image
Since the given triangle is a right-angled triangle, we can apply the special trig functions
<u>These functions are as follows:</u>
sin(θ) = opposite / hypotenuse
cos(θ) = adjacent / hypotenuse
tan(θ) = opposite / adjacent
<u>Now, in the given diagram:</u>
θ = 40°
AC is the side opposite to θ
AB = 10 in is the hypotenuse
<u>Based on these givens</u>, we will use the sin(θ) function
<u>Therefore:</u>

1) subtract 2y in both sides: (7y-2y)-6=(2y-2y)+8 which is 5y-6=8
2) Add 6 to both sides: 5y(-6+6)=8+6 which is 5y=14
3) Divide 5 on both sides: 5y/5=14/5 which is y=14/5 or y=2.8 or y=2 4/5