Step-by-step explanation:
To prove :
( 1 - sin x ) ( 1 + sin x ) = sec² x
LHS : -
( 1 - sin x ) ( 1 + sin x )
Formula / Identity : -
( a - b ) ( a + b ) = a² - b²
Here,
a = 1
b = sin x
( 1 - sin x ) ( 1 + sin x )
= 1 - sin² x
Identify : -
sin² θ + cos² θ = 1
cos² θ = 1 - sin² θ
Similarly,
1 - sin² x
= cos² x
= RHS
Hence verified.
Answer:
Part A: Option 2, A: Anna’s answer is incorrect. She correctly factored out 5x, but incorrectly identified a and b, so her answer cannot be correct.
Part B: Option 3, B: 5x(x+2)(x^2−2x+4)
Step-by-step explanation:
p(x) = 5x^4 + 40x
p(x) = 5x(x^3 + 8)
p(x) = 5x(x + 2)(x^2 - 2x + 4)
Part A: Option 2, A: Anna’s answer is incorrect. She correctly factored out 5x, but incorrectly identified a and b, so her answer cannot be correct.
Part B: Option 3, B: 5x(x+2)(x^2−2x+4)
Answer: a. Area b. 4222.26
