rewrite the factor sec u in the first term, cos u sec u, in terms of cos u. cos u•1/cos u - cos²u simplify…

rewrite the factor sec u in the first term, cos u sec u, in terms of cos u. cos u•1/cos u - cos²u simplify the expression from the previous step by canceling the common factor. - cos²u

rewrite the factor sec u in the first term, cos u sec u, in terms of cos u. cos u•1/cos u - cos²u simplify the expression from the previous step by canceling the common factor. - cos²u

Answer

Explanation:

Step1: Recall secant - cosine relation

We know that $\sec u=\frac{1}{\cos u}$, so $\cos u\cdot\sec u=\cos u\cdot\frac{1}{\cos u}$.

Step2: Cancel common factor

When we have $\cos u\cdot\frac{1}{\cos u}$, the $\cos u$ terms cancel out. Since $\frac{\cos u}{\cos u} = 1$ for $\cos u\neq0$, the simplified first - term is $1$.

Answer:

$1$