the answer is letter A. 8/1
70 percent off 19.50 would mean getting a discount of 13.65, so the final price of the sandals by the end of the summer should be 5.85
Answer:
f(x) = sec x. tan x
⇔ f(x) = 1/cosx . cosx/sinx
⇔ f(x) = sin x
+) when f(x) is increasing => sin x increases
=> x will increase
+) f(x) is decreasing => x will decrease
+) f(x) is concave up => x ∈ (-pi/2; 0)
+) f(x) concave down => x ∈ (0; pi/2)
Step-by-step explanation: