Let F––(t)=t2i–+tj–+k––𝐹_(𝑡)=𝑡2𝑖_+𝑡𝑗_+𝑘_ and G––(t)=i–+tj–+t2k––𝐺_(𝑡)=𝑖_+𝑡𝑗_+𝑡2𝑘_ be two vector functions defined for each t∈R𝑡∈𝑅. (a) The derivative of F––(t)×G––(t)𝐹_(𝑡)×𝐺_(𝑡) with respect to t𝑡, at t=1𝑡=1 is given by
Question
Let F––(t)=t2i–+tj–+k––𝐹_(𝑡)=𝑡2𝑖_+𝑡𝑗_+𝑘_ and G––(t)=i–+tj–+t2k––𝐺_(𝑡)=𝑖_+𝑡𝑗_+𝑡2𝑘_ be two vector functions defined for each t∈R𝑡∈𝑅. (a) The derivative of F––(t)×G––(t)𝐹_(𝑡)×𝐺_(𝑡) with respect to t𝑡, at t=1𝑡=1 is given by
Solution 1
To find the derivative of the cross product F(t) x G(t), we first need to find the cross product of F(t) and G(t).
The cross product of two vectors is given by the determinant of a 3x3 matrix. The first row of the matrix is the unit vectors i, j, k. The second row is the coefficients of the vector F(t), and the third row is the coefficients of the vector G(t).
So, we have:
F(t) x G(t) = det | i j k | | t² t 1 | | 1 t t² |
= i(t² - t) - j(t² - t) + k(t² - t)
= (t² - t)i - (t² - t)j + (t² - t)k
Now, we need to find the derivative of this with respect to t.
d/dt [F(t) x G(t)] = d/dt [(t² - t)i - (t² - t)j + (t² - t)k]
= [2t - 1]i - [2t - 1]j + [2t - 1]k
Finally, we substitute t = 1 to find the derivative at t = 1:
d/dt [F(1) x G(1)] = [21 - 1]i - [21 - 1]j + [2*1 - 1]k
= i - j + k
So, the derivative of F(t) x G(t) with respect to t, at t = 1 is i - j + k.
Solution 2
To find the derivative of the cross product F(t) x G(t), we first need to find the cross product of the two vector functions F(t) and G(t).
The cross product of two vectors is given by the determinant of a 3x3 matrix. The first row of the matrix is the unit vectors i, j, and k. The second row is the coefficients of the vector F(t), and the third row is the coefficients of the vector G(t).
So, the cross product F(t) x G(t) is:
i(t^2 - t) - j(t^2 - 1) + k(t - t^2)
Next, we need to find the derivative of this cross product with respect to t.
The derivative of a vector function is found by taking the derivative of each component of the vector.
So, the derivative of F(t) x G(t) is:
i(2t - 1) - j(2t) + k(1 - 2t)
Finally, we need to evaluate this derivative at t = 1.
Substituting t = 1 into the derivative gives:
i(21 - 1) - j(21) + k(1 - 2*1)
So, the derivative of F(t) x G(t) at t = 1 is:
i(1) - j(2) - k(1)
Similar Questions
Now let H––(t)=t3i–+t2j–+tk––𝐻_(𝑡)=𝑡3𝑖_+𝑡2𝑗_+𝑡𝑘_ be another vector function defined for each t∈R𝑡∈𝑅. The derivative of (F––(t)×G––(t)).H––(t)(𝐹_(𝑡)×𝐺_(𝑡)).𝐻_(𝑡) with respect to t𝑡, at t=1𝑡=1 is given by Answer
Let F––(t)=t2i–+tj–+k––𝐹_(𝑡)=𝑡2𝑖_+𝑡𝑗_+𝑘_ and G––(t)=i–+tj–+t2k––𝐺_(𝑡)=𝑖_+𝑡𝑗_+𝑡2𝑘_ be two vector functions defined for each t∈R𝑡∈𝑅.
Let F––(t)=2ti–−5j–+t2k––𝐹_(𝑡)=2𝑡𝑖_−5𝑗_+𝑡2𝑘_ and G––(t)=(1−t)i–+1tk––𝐺_(𝑡)=(1−𝑡)𝑖_+1𝑡𝑘_ where t∈R+𝑡∈𝑅+.
Differentiate the following functions w.r.t. 𝒙.(i) 8𝑥−34
For general vector fields F and G prove that∇ × (F + G) = ∇ × F + ∇ × G,[6 marks]∇ • (F × G) = G • (∇ × F) − F • (∇ × G)
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