Here are the solutions to your tasks:
a) Help John to know the length of the remaining sides and angle of the remaining vertex.
Step 1: Determine the third angle of the triangular apparatus.
The sum of angles in a triangle is 180∘. Given angles are 59∘ and 73∘.
Remainingangle=180∘−59∘−73∘
Remainingangle=180∘−132∘
Remainingangle=48∘
The angle of the remaining vertex is 48∘.
Step 2: Use the Sine Rule to find the lengths of the remaining sides.
Let the given side be c=12 ft, opposite the 48∘ angle. Let the other angles be A=59∘ and B=73∘, with opposite sides a and b respectively.
The Sine Rule states: sinAa=sinBb=sinCc.
We have sin59∘a=sin73∘b=sin48∘12.
Step 3: Calculate side a.
a=sin48∘12sin59∘
a≈0.743112×0.8572
a≈0.743110.2864
a≈13.84ft
The length of one remaining side is 13.84 ft.
Step 4: Calculate side b.
b=sin48∘12sin73∘
b≈0.743112×0.9563
b≈0.743111.4756
b≈15.44ft
The length of the other remaining side is 15.44 ft.
b) Guide the learners on how to come up with the angle in the experiment present them in a solution set.
Step 1: Rewrite the given equation using trigonometric identities.
The equation is 5secθ−2sec2θ=tan2θ−1.
Recall the identity sec2θ=1+tan2θ, which implies tan2θ=sec2θ−1.
Substitute tan2θ−1 with (sec2θ−1)−1:
5secθ−2sec2θ=(sec2θ−1)−1
5secθ−2sec2θ=sec2θ−2
Step 2: Rearrange the equation into a quadratic form.
Move all terms to one side to form a quadratic equation in terms of secθ:
0=sec2θ+2sec2θ−5secθ−2
3sec2θ−5secθ−2=0
Step 3: Solve the quadratic equation for secθ.
Let x=secθ. The equation becomes 3x2−5x−2=0.
Factor the quadratic equation:
(3x+1)(x−2)=0
This gives two possible values for x:
3x+1=0⟹x=−31
x−2=0⟹x=2
So, secθ=−31 or secθ=2.
Step 4: Convert to cosθ and find the angles θ in the range 0∘≤θ≤360∘.
Since secθ=cosθ1, we have cosθ=secθ1.
Case 1: cosθ=−1/31=−3. This is not possible because the range of cosθ is [−1,1]. So, there are no solutions from this case.
Case 2: cosθ=21.
The principal value (reference angle) for cosθ=21 is α=cos−1(21)=60∘.
Since cosθ is positive, θ lies in Quadrant I and Quadrant IV.
In Quadrant I: θ1=α=60∘.
In Quadrant IV: θ2=360∘−α=360∘−60∘=300∘.
The solution set for θ is {60∘,300∘}.
c) Take the students through the steps on how tanB=1+2tanA−tan2A1−2tanA−tan2A holds.
Given that B=45∘−2A. We need to show that tanB equals the given expression.
Step 1: Apply the tangent subtraction formula.
The formula for tan(X−Y) is tan(X−Y)=1+tanXtanYtanX−tanY.
Substitute X=45∘ and Y=2A:
tanB=tan(45∘−2A)=1+tan45∘tan2Atan45∘−tan2A
Step 2: Substitute the value of tan45∘.
We know that tan45∘=1.
tanB=1+1⋅tan2A1−tan2A
tanB=1+tan2A1−tan2A
Step 3: Apply the tangent double angle formula.
The formula for tan2A is tan2A=1−tan2A2tanA.
Step 4: Substitute the expression for tan2A into the equation for tanB.
tanB=1+(1−tan2A2tanA)1−(1−tan2A2tanA)
Step 5: Simplify the complex fraction by multiplying the numerator and denominator by (1−tan2A).
tanB=(1−tan2A)⋅1+(1−tan2A)⋅(1−tan2A2tanA)(1−tan2A)⋅1−(1−tan2A)⋅(1−tan2A2tanA)
tanB=(1−tan2A)+2tanA(1−tan2A)−2tanA
Step 6: Rearrange the terms in the numerator and denominator.
tanB=1+2tanA−tan2A1−2tanA−tan2A
This matches the expression given by the student, thus showing how it holds.
3 done, 2 left today. You're making progress.