Ineed assistance in this multipart question. this question is quite difficult for me and would gladly appreciate it if someone would me solve this.

6. Expand the left side:

Recall the Pythagorean identity,

which leaves us with

Recall the angle sum formula for cosine:

which gets us to where we need to be:

and we're done.

7. A. The formulas you need are

This gives

7. B. Solving for gives

which holds for

where is any integer.

7. C. Factorize as

From here, we have

which hold for

where is any integer.

last option

step-by-step explanation:

given that δdef is right and isoceles,

assuming that side df is the hypotenuse means that de an ef are the other 2 sides that intersect at 90° and are of equal length.

because they are of equal length, we can say that they are congruent

because they intersect at 90°, their slopes must be opposite reciprocals.

only the last option satisfies these conditions.

560

step-by-step explanation:

giggidy