Question

$\overset{\rightarrow}{r(t)}=tan^{-1}ti+sintj+t^2k$ ആയാൽ $\overset{\rightarrow}{r'(t)}_{t=0}=$

• A. i-j
• B. 1/2i+j+k
• C. i+j-k
• D. i+j

Answer 1

Answer:

D. i+j

$\overset{\rightarrow}{r'(t)}=\frac{1}{1+t^2}i+costj +2tk$

$\overset{\rightarrow}{r'(t)}_{t=0}=\frac{1}{1+0}i+cos0+2 \times 0k$

$=i+j$