Final answer:
The question seems to be asking for the angle between two functions over an interval, but it does not provide a clear method for calculating such an angle and appears to be based on a misunderstanding.
Step-by-step explanation:
The question asks to find the angle between two functions, f1(t) = 2t² + 3 and f2(t) = sin(t), for t in the interval [0, 1]. To find the angle between two functions over an interval, one would typically look at the inner product (also known as the dot product in vector spaces) of the functions and use the cosine formula for the angle between them. However, since this question does not provide sufficient context or a clear definition of the inner product for functions, most likely due to a misunderstanding, we cannot determine the angle. In typical scenarios involving vectors, the angle θ between two vectors A and B can be found using the formula cos(θ) = (A ⋅ B) / (||A|| ||B||) where A ⋅ B denotes the dot product of A and B and ||A|| and ||B|| are the magnitudes (norms) of A and B respectively.