Let $C[0,1]$ be the Real vector space of all the continuous Real valued function

linear algebraoperator-theory

Given that Let $C[0,1]$ be the Real vector space of all the continous Real valued function on $[0,1]$ let $T$ be the linear operator on this and defined by

$$(Tf)(x)=\int_0^1 \sin(x+y)f(y) \;dy\;\;,\;x \in [0,1]$$

find the Dimensions of Range space of $T$

Solution I tried-The given transformation is a operator So it will defined like $$T:C[0,1]\rightarrow C[0,1]$$ after that i have no idea how to solve ,Please provide me a hint

Thank you

Best Answer

$Tf(x)=\int_0^{1} [\sin x\cos y+\cos x \sin y ]f(y)dy=a\sin x+b \cos x$ where $a=\int_0^{1} \cos y f(y)dy$ and $b=\int_0^{1} \sin y f(y)dy$. Hence the range is contained in the two dimensional space spanned by $\sin x$ and $\cos x$. I will leave it to you to check that these two functions are actually in the range (or some linear combinations of these which are not scalar multiples of each other are in the range). Hence the range is 2-dimensional.